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Publisher: Elsevier   (Total: 3043 journals)

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Showing 1 - 200 of 3043 Journals sorted alphabetically
AASRI Procedia     Open Access   (Followers: 15)
Academic Pediatrics     Hybrid Journal   (Followers: 20, SJR: 1.402, h-index: 51)
Academic Radiology     Hybrid Journal   (Followers: 18, SJR: 1.008, h-index: 75)
Accident Analysis & Prevention     Partially Free   (Followers: 83, SJR: 1.109, h-index: 94)
Accounting Forum     Hybrid Journal   (Followers: 23, SJR: 0.612, h-index: 27)
Accounting, Organizations and Society     Hybrid Journal   (Followers: 27, SJR: 2.515, h-index: 90)
Achievements in the Life Sciences     Open Access   (Followers: 4)
Acta Anaesthesiologica Taiwanica     Open Access   (Followers: 5, SJR: 0.338, h-index: 19)
Acta Astronautica     Hybrid Journal   (Followers: 333, SJR: 0.726, h-index: 43)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 3)
Acta Biomaterialia     Hybrid Journal   (Followers: 25, SJR: 2.02, h-index: 104)
Acta Colombiana de Cuidado Intensivo     Full-text available via subscription   (Followers: 1)
Acta de Investigación Psicológica     Open Access   (Followers: 2)
Acta Ecologica Sinica     Open Access   (Followers: 8, SJR: 0.172, h-index: 29)
Acta Haematologica Polonica     Free   (SJR: 0.123, h-index: 8)
Acta Histochemica     Hybrid Journal   (Followers: 3, SJR: 0.604, h-index: 38)
Acta Materialia     Hybrid Journal   (Followers: 225, SJR: 3.683, h-index: 202)
Acta Mathematica Scientia     Full-text available via subscription   (Followers: 5, SJR: 0.615, h-index: 21)
Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9, SJR: 0.442, h-index: 21)
Acta Oecologica     Hybrid Journal   (Followers: 9, SJR: 0.915, h-index: 53)
Acta Otorrinolaringologica (English Edition)     Full-text available via subscription   (Followers: 1)
Acta Otorrinolaringológica Española     Full-text available via subscription   (Followers: 3, SJR: 0.311, h-index: 16)
Acta Pharmaceutica Sinica B     Open Access   (Followers: 2)
Acta Poética     Open Access   (Followers: 4)
Acta Psychologica     Hybrid Journal   (Followers: 23, SJR: 1.365, h-index: 73)
Acta Sociológica     Open Access  
Acta Tropica     Hybrid Journal   (Followers: 6, SJR: 1.059, h-index: 77)
Acta Urológica Portuguesa     Open Access  
Actas Dermo-Sifiliograficas     Full-text available via subscription   (Followers: 4)
Actas Dermo-Sifiliográficas (English Edition)     Full-text available via subscription   (Followers: 3)
Actas Urológicas Españolas     Full-text available via subscription   (Followers: 4, SJR: 0.383, h-index: 19)
Actas Urológicas Españolas (English Edition)     Full-text available via subscription   (Followers: 2)
Actualites Pharmaceutiques     Full-text available via subscription   (Followers: 5, SJR: 0.141, h-index: 3)
Actualites Pharmaceutiques Hospitalieres     Full-text available via subscription   (Followers: 4, SJR: 0.112, h-index: 2)
Acupuncture and Related Therapies     Hybrid Journal   (Followers: 3)
Ad Hoc Networks     Hybrid Journal   (Followers: 11, SJR: 0.967, h-index: 57)
Addictive Behaviors     Hybrid Journal   (Followers: 15, SJR: 1.514, h-index: 92)
Addictive Behaviors Reports     Open Access   (Followers: 5)
Additive Manufacturing     Hybrid Journal   (Followers: 8, SJR: 1.039, h-index: 5)
Additives for Polymers     Full-text available via subscription   (Followers: 20)
Advanced Drug Delivery Reviews     Hybrid Journal   (Followers: 134, SJR: 5.2, h-index: 222)
Advanced Engineering Informatics     Hybrid Journal   (Followers: 11, SJR: 1.265, h-index: 53)
Advanced Powder Technology     Hybrid Journal   (Followers: 16, SJR: 0.739, h-index: 33)
Advances in Accounting     Hybrid Journal   (Followers: 9, SJR: 0.299, h-index: 15)
Advances in Agronomy     Full-text available via subscription   (Followers: 15, SJR: 2.071, h-index: 82)
Advances in Anesthesia     Full-text available via subscription   (Followers: 25, SJR: 0.169, h-index: 4)
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 3)
Advances in Applied Mathematics     Full-text available via subscription   (Followers: 6, SJR: 1.054, h-index: 35)
Advances in Applied Mechanics     Full-text available via subscription   (Followers: 10, SJR: 0.801, h-index: 26)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 22, SJR: 1.286, h-index: 49)
Advances In Atomic, Molecular, and Optical Physics     Full-text available via subscription   (Followers: 16, SJR: 3.31, h-index: 42)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4, SJR: 2.277, h-index: 43)
Advances in Botanical Research     Full-text available via subscription   (Followers: 3, SJR: 0.619, h-index: 48)
Advances in Cancer Research     Full-text available via subscription   (Followers: 25, SJR: 2.215, h-index: 78)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 9, SJR: 0.9, h-index: 30)
Advances in Catalysis     Full-text available via subscription   (Followers: 5, SJR: 2.139, h-index: 42)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 12)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 24, SJR: 0.183, h-index: 23)
Advances in Child Development and Behavior     Full-text available via subscription   (Followers: 10, SJR: 0.665, h-index: 29)
Advances in Chronic Kidney Disease     Full-text available via subscription   (Followers: 10, SJR: 1.268, h-index: 45)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 28, SJR: 0.938, h-index: 33)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18, SJR: 2.314, h-index: 130)
Advances in Computers     Full-text available via subscription   (Followers: 16, SJR: 0.223, h-index: 22)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 11)
Advances in Digestive Medicine     Open Access   (Followers: 4)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 5)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Ecological Research     Full-text available via subscription   (Followers: 42, SJR: 3.25, h-index: 43)
Advances in Engineering Software     Hybrid Journal   (Followers: 25, SJR: 0.486, h-index: 10)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 7)
Advances in Experimental Social Psychology     Full-text available via subscription   (Followers: 40, SJR: 5.465, h-index: 64)
Advances in Exploration Geophysics     Full-text available via subscription   (Followers: 3)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
Advances in Food and Nutrition Research     Full-text available via subscription   (Followers: 47, SJR: 0.674, h-index: 38)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Genetics     Full-text available via subscription   (Followers: 15, SJR: 2.558, h-index: 54)
Advances in Genome Biology     Full-text available via subscription   (Followers: 11)
Advances in Geophysics     Full-text available via subscription   (Followers: 6, SJR: 2.325, h-index: 20)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 21, SJR: 0.906, h-index: 24)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8, SJR: 0.497, h-index: 31)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 26)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 2, SJR: 0.396, h-index: 27)
Advances in Immunology     Full-text available via subscription   (Followers: 35, SJR: 4.152, h-index: 85)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 9, SJR: 1.132, h-index: 42)
Advances in Insect Physiology     Full-text available via subscription   (Followers: 3, SJR: 1.274, h-index: 27)
Advances in Integrative Medicine     Hybrid Journal   (Followers: 5)
Advances in Intl. Accounting     Full-text available via subscription   (Followers: 4)
Advances in Life Course Research     Hybrid Journal   (Followers: 8, SJR: 0.764, h-index: 15)
Advances in Lipobiology     Full-text available via subscription   (Followers: 2)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Marine Biology     Full-text available via subscription   (Followers: 16, SJR: 1.645, h-index: 45)
Advances in Mathematics     Full-text available via subscription   (Followers: 10, SJR: 3.261, h-index: 65)
Advances in Medical Sciences     Hybrid Journal   (Followers: 6, SJR: 0.489, h-index: 25)
Advances in Medicinal Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Microbial Physiology     Full-text available via subscription   (Followers: 4, SJR: 1.44, h-index: 51)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 22)
Advances in Molecular and Cellular Endocrinology     Full-text available via subscription   (Followers: 10)
Advances in Molecular Toxicology     Full-text available via subscription   (Followers: 7, SJR: 0.324, h-index: 8)
Advances in Nanoporous Materials     Full-text available via subscription   (Followers: 4)
Advances in Oncobiology     Full-text available via subscription   (Followers: 3)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15, SJR: 2.885, h-index: 45)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7, SJR: 0.148, h-index: 11)
Advances in Parasitology     Full-text available via subscription   (Followers: 7, SJR: 2.37, h-index: 73)
Advances in Pediatrics     Full-text available via subscription   (Followers: 24, SJR: 0.4, h-index: 28)
Advances in Pharmaceutical Sciences     Full-text available via subscription   (Followers: 13)
Advances in Pharmacology     Full-text available via subscription   (Followers: 15, SJR: 1.718, h-index: 58)
Advances in Physical Organic Chemistry     Full-text available via subscription   (Followers: 7, SJR: 0.384, h-index: 26)
Advances in Phytomedicine     Full-text available via subscription  
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3, SJR: 0.248, h-index: 11)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 8)
Advances in Plant Pathology     Full-text available via subscription   (Followers: 5)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 19, SJR: 1.5, h-index: 62)
Advances in Psychology     Full-text available via subscription   (Followers: 60)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5, SJR: 0.478, h-index: 32)
Advances in Radiation Oncology     Open Access  
Advances in Small Animal Medicine and Surgery     Hybrid Journal   (Followers: 2, SJR: 0.1, h-index: 2)
Advances in Space Research     Full-text available via subscription   (Followers: 345, SJR: 0.606, h-index: 65)
Advances in Structural Biology     Full-text available via subscription   (Followers: 8)
Advances in Surgery     Full-text available via subscription   (Followers: 7, SJR: 0.823, h-index: 27)
Advances in the Study of Behavior     Full-text available via subscription   (Followers: 30, SJR: 1.321, h-index: 56)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 16)
Advances in Veterinary Science and Comparative Medicine     Full-text available via subscription   (Followers: 13)
Advances in Virus Research     Full-text available via subscription   (Followers: 5, SJR: 1.878, h-index: 68)
Advances in Water Resources     Hybrid Journal   (Followers: 43, SJR: 2.408, h-index: 94)
Aeolian Research     Hybrid Journal   (Followers: 5, SJR: 0.973, h-index: 22)
Aerospace Science and Technology     Hybrid Journal   (Followers: 310, SJR: 0.816, h-index: 49)
AEU - Intl. J. of Electronics and Communications     Hybrid Journal   (Followers: 8, SJR: 0.318, h-index: 36)
African J. of Emergency Medicine     Open Access   (Followers: 5, SJR: 0.344, h-index: 6)
Ageing Research Reviews     Hybrid Journal   (Followers: 8, SJR: 3.289, h-index: 78)
Aggression and Violent Behavior     Hybrid Journal   (Followers: 408, SJR: 1.385, h-index: 72)
Agri Gene     Hybrid Journal  
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 15, SJR: 2.18, h-index: 116)
Agricultural Systems     Hybrid Journal   (Followers: 30, SJR: 1.275, h-index: 74)
Agricultural Water Management     Hybrid Journal   (Followers: 38, SJR: 1.546, h-index: 79)
Agriculture and Agricultural Science Procedia     Open Access  
Agriculture and Natural Resources     Open Access   (Followers: 1)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 53, SJR: 1.879, h-index: 120)
Ain Shams Engineering J.     Open Access   (Followers: 5, SJR: 0.434, h-index: 14)
Air Medical J.     Hybrid Journal   (Followers: 5, SJR: 0.234, h-index: 18)
AKCE Intl. J. of Graphs and Combinatorics     Open Access   (SJR: 0.285, h-index: 3)
Alcohol     Hybrid Journal   (Followers: 9, SJR: 0.922, h-index: 66)
Alcoholism and Drug Addiction     Open Access   (Followers: 6)
Alergologia Polska : Polish J. of Allergology     Full-text available via subscription   (Followers: 1)
Alexandria Engineering J.     Open Access   (Followers: 1, SJR: 0.436, h-index: 12)
Alexandria J. of Medicine     Open Access  
Algal Research     Partially Free   (Followers: 8, SJR: 2.05, h-index: 20)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
Allergologia et Immunopathologia     Full-text available via subscription   (Followers: 1, SJR: 0.46, h-index: 29)
Allergology Intl.     Open Access   (Followers: 4, SJR: 0.776, h-index: 35)
ALTER - European J. of Disability Research / Revue Européenne de Recherche sur le Handicap     Full-text available via subscription   (Followers: 7, SJR: 0.158, h-index: 9)
Alzheimer's & Dementia     Hybrid Journal   (Followers: 48, SJR: 4.289, h-index: 64)
Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring     Open Access   (Followers: 5)
Alzheimer's & Dementia: Translational Research & Clinical Interventions     Open Access   (Followers: 3)
American Heart J.     Hybrid Journal   (Followers: 48, SJR: 3.157, h-index: 153)
American J. of Cardiology     Hybrid Journal   (Followers: 45, SJR: 2.063, h-index: 186)
American J. of Emergency Medicine     Hybrid Journal   (Followers: 38, SJR: 0.574, h-index: 65)
American J. of Geriatric Pharmacotherapy     Full-text available via subscription   (Followers: 6, SJR: 1.091, h-index: 45)
American J. of Geriatric Psychiatry     Hybrid Journal   (Followers: 16, SJR: 1.653, h-index: 93)
American J. of Human Genetics     Hybrid Journal   (Followers: 31, SJR: 8.769, h-index: 256)
American J. of Infection Control     Hybrid Journal   (Followers: 24, SJR: 1.259, h-index: 81)
American J. of Kidney Diseases     Hybrid Journal   (Followers: 33, SJR: 2.313, h-index: 172)
American J. of Medicine     Hybrid Journal   (Followers: 46, SJR: 2.023, h-index: 189)
American J. of Medicine Supplements     Full-text available via subscription   (Followers: 3)
American J. of Obstetrics and Gynecology     Hybrid Journal   (Followers: 187, SJR: 2.255, h-index: 171)
American J. of Ophthalmology     Hybrid Journal   (Followers: 54, SJR: 2.803, h-index: 148)
American J. of Ophthalmology Case Reports     Open Access   (Followers: 3)
American J. of Orthodontics and Dentofacial Orthopedics     Full-text available via subscription   (Followers: 6, SJR: 1.249, h-index: 88)
American J. of Otolaryngology     Hybrid Journal   (Followers: 23, SJR: 0.59, h-index: 45)
American J. of Pathology     Hybrid Journal   (Followers: 26, SJR: 2.653, h-index: 228)
American J. of Preventive Medicine     Hybrid Journal   (Followers: 21, SJR: 2.764, h-index: 154)
American J. of Surgery     Hybrid Journal   (Followers: 34, SJR: 1.286, h-index: 125)
American J. of the Medical Sciences     Hybrid Journal   (Followers: 12, SJR: 0.653, h-index: 70)
Ampersand : An Intl. J. of General and Applied Linguistics     Open Access   (Followers: 5)
Anaerobe     Hybrid Journal   (Followers: 4, SJR: 1.066, h-index: 51)
Anaesthesia & Intensive Care Medicine     Full-text available via subscription   (Followers: 55, SJR: 0.124, h-index: 9)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 9)
Anales de Cirugia Vascular     Full-text available via subscription  
Anales de Pediatría     Full-text available via subscription   (Followers: 2, SJR: 0.209, h-index: 27)
Anales de Pediatría (English Edition)     Full-text available via subscription  
Anales de Pediatría Continuada     Full-text available via subscription   (SJR: 0.104, h-index: 3)
Analytic Methods in Accident Research     Hybrid Journal   (Followers: 2, SJR: 2.577, h-index: 7)
Analytica Chimica Acta     Hybrid Journal   (Followers: 38, SJR: 1.548, h-index: 152)
Analytical Biochemistry     Hybrid Journal   (Followers: 164, SJR: 0.725, h-index: 154)
Analytical Chemistry Research     Open Access   (Followers: 8, SJR: 0.18, h-index: 2)
Analytical Spectroscopy Library     Full-text available via subscription   (Followers: 11)
Anesthésie & Réanimation     Full-text available via subscription   (Followers: 1)
Anesthesiology Clinics     Full-text available via subscription   (Followers: 22, SJR: 0.421, h-index: 40)
Angiología     Full-text available via subscription   (SJR: 0.124, h-index: 9)
Angiologia e Cirurgia Vascular     Open Access  
Animal Behaviour     Hybrid Journal   (Followers: 158, SJR: 1.907, h-index: 126)
Animal Feed Science and Technology     Hybrid Journal   (Followers: 5, SJR: 1.151, h-index: 83)
Animal Reproduction Science     Hybrid Journal   (Followers: 5, SJR: 0.711, h-index: 78)
Annales d'Endocrinologie     Full-text available via subscription   (Followers: 1, SJR: 0.394, h-index: 30)
Annales d'Urologie     Full-text available via subscription  
Annales de Cardiologie et d'Angéiologie     Full-text available via subscription   (SJR: 0.177, h-index: 13)
Annales de Chirurgie de la Main et du Membre Supérieur     Full-text available via subscription  
Annales de Chirurgie Plastique Esthétique     Full-text available via subscription   (Followers: 2, SJR: 0.354, h-index: 22)
Annales de Chirurgie Vasculaire     Full-text available via subscription   (Followers: 1)

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Journal Cover Aerospace Science and Technology
  [SJR: 0.816]   [H-I: 49]   [310 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1270-9638
   Published by Elsevier Homepage  [3043 journals]
  • Mission performance analysis of a conceptual coaxial rotorcraft for air
           taxi applications
    • Authors: J. Enconniere; J. Ortiz-Carretero; V. Pachidis
      Pages: 1 - 14
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): J. Enconniere, J. Ortiz-Carretero, V. Pachidis
      The rotorcraft industry has recently shown a new interest in compound rotorcraft as a feasible alternative to tackle the rapid growth of civil aviation activities and associated environmental impact. Indeed, aircraft contribution to the global emissions of CO 2 , NO x , and noise are driving the development of innovative technologies and vehicles. At present, compound rotorcraft architectures are regarded by the industry as promising platforms that can potentially increase productivity at a reduced environmental cost. In order to quantify the benefits of compound rotorcraft, this paper details the performance analysis of a coaxial counter-rotating rotor configuration with a pusher propeller. A comprehensive approach targeting the assessment of the aforementioned rotorcraft design for civil applications is presented herein. The methodology developed encompasses a rotorcraft flight dynamics simulation module and an engine performance module, coupled with a gaseous emissions prediction tool for environmental impact studies. They have been integrated together to constitute a standalone performance simulation framework and verified with the performance calculations of Harrington's “rotor 1” and the Sikorsky X2TD. The method is then applied to evaluate the performance of a conceptual coaxial rotorcraft, during a notional inter-city air taxi mission, in terms of cruise altitude, speed, and range, overall mission time and environmental impact. The several trade-offs between these parameters highlight the need for an integrated optimisation process. Besides, the concept demonstrates the benefits of the compound rotorcraft architecture with a best range speed reaching 90 m/s leading to reduced response times and increase of round trips in a given time. As a consequence, operators will need fewer vehicles and heliports to cover the same areas. This outcome is highly attractive in the current growing market.

      PubDate: 2017-07-08T07:35:38Z
      DOI: 10.1016/j.ast.2017.06.015
      Issue No: Vol. 69 (2017)
       
  • Model reduction for flight dynamics simulations using computational fluid
           dynamics
    • Authors: Giampaolo Pagliuca; Sebastian Timme
      Pages: 15 - 26
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Giampaolo Pagliuca, Sebastian Timme
      Multidisciplinary simulation involving flight dynamics and computational fluid dynamics is required for high-fidelity gust loads analysis in transonic flow. However, the main limitation to a more routine use is prohibitive computational cost involved. A promising trade-off between accuracy and low-cost is model reduction of high-fidelity methods. Thus investigation of such reduction of coupled models is presented. The reduction technique relies on an expansion of the full order non-linear residual function in a truncated Taylor series and subsequent projection onto a small modal basis. Two procedures are discussed to obtain modes for the projection. First, an operator-based identification is exploited to calculate eigenpairs of the coupled Jacobian matrix related to the flight dynamics degrees-of-freedom. Secondly, proper orthogonal decomposition is used as a data-based method to obtain modes representing the system subject to external disturbance such as gusts. Benefits and limitations of the various methods are investigated by analysing results for initial disturbance and gust encounter simulations. Overall, reduced order models based on the presented approaches are able to retain the accuracy of the high-fidelity tools to predict accurately flight dynamics responses and loads while reducing the computational cost up to two orders of magnitude.

      PubDate: 2017-07-08T07:35:38Z
      DOI: 10.1016/j.ast.2017.06.013
      Issue No: Vol. 69 (2017)
       
  • Adaptive fault tolerant attitude tracking control for miniature
           rotorcrafts under actuator saturation
    • Authors: Zhankui Song; Shuai Ling; Kaibiao Sun
      Pages: 27 - 38
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Zhankui Song, Shuai Ling, Kaibiao Sun
      The problem of attitude tracking control for a miniature rotorcraft with partial loss of actuator effectiveness is investigated in this paper. By using adaptation mechanism and by combining with Nussbaum gain technique, an adaptive tolerant control strategy capable of attenuating immeasurable disturbances, compensating system parameters uncertainties, and accommodating actuation faults is developed. Then, the rotorcraft attitude system subjected to control constraints is further considered, and a novel fault tolerant controller equipped with auxiliary systems is designed to achieve both attitude tracking and saturation alleviation of control signal. Moreover, fault detection and diagnosis unit are not needed in using and implementing the proposed method. It is proven that attitude errors can asymptotically converge to a small neighborhood of equilibrium point in the face of faulty actuator, model uncertainties, external disturbances and even actuator saturation. Finally, the simulation results demonstrate the effectiveness of the proposed controller.

      PubDate: 2017-07-08T07:35:38Z
      DOI: 10.1016/j.ast.2017.06.005
      Issue No: Vol. 69 (2017)
       
  • Quasi-1D analysis and performance estimation of a sub-scale RBCC engine
           with chemical equilibrium
    • Authors: Hye-Sung Kim; Sejong Oh; Jeong-Yeol Choi
      Pages: 39 - 47
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Hye-Sung Kim, Sejong Oh, Jeong-Yeol Choi
      In this study, quasi-1D analysis with chemical equilibrium was applied at a sub-scale rocket-based combined cycle (RBCC) engine for a hypersonic flight test using a sounding rocket. A mission profile of the engine was designed in a previous study, and its off-design performance was examined in test-mission research for the flight test. The operational conditions are Mach 3 to 7 at altitudes of 10 to 30 km. A bleed duct and a pre-burner are applied in the engine. The analysis method was validated by comparison with HyShot II flight test data to ensure reliability. The thrust and the specific impulse at each design point are 595 N and 646 s in scramjet mode, while they are 9.07 kN and 1,543 s in ramjet mode.

      PubDate: 2017-07-08T07:35:38Z
      DOI: 10.1016/j.ast.2017.06.019
      Issue No: Vol. 69 (2017)
       
  • Modern approach to study trends in global ultraviolet index maps variation
           over solar cycles by the complementary use of time series, mathematical
           metrics and artificial neural networks
    • Authors: Magdalena Latosińska; Jolanta Natalia Latosińska
      Pages: 48 - 59
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Magdalena Latosińska, Jolanta Natalia Latosińska
      The information on how much total solar energy and its ultraviolet component can be acquired from the Sun at particular locations is vital for climatology, ecology, health-care but also for some branches of modern industry (e.g. constructions, solar power technologies, materials science, pharmacy, optometry and optics). The Discrete Fourier Transform applied to study UV index (UVI) time series in the last solar cycle at selected locations (71 in Europe and 114 in the World) has revealed periodicity and correlation between the amplitude and latitude. The main frequency peak with amplitude varying from 0.963 to 5.625 shows the UVI periodicity of 315–316 days at each location. The greatest variation in UVI occurs at two latitude bands distanced by 65° (Northern hemisphere from 30° to 50° and Southern hemisphere from −50° to −20°); the lowest variation is observed near the equatorial region. A completely novel method for a comparative analysis of UVI measured by satellites (Nimbus-7/TOMS (Total Ozone Mapping Spectrometer), 1978–1991; Meteor-3/TOMS, 1991–1995; Earth-Probe/TOMS, 1996–2005) for the whole globe in the range from 1978 to 2005, has been developed and applied. A few mathematical metrics (Manhattan, Euclidean, Bhattacharyya, Hellinger) applied for the studies of monthly averaged maps of UVI from 1978 to 2005 reveal different character of UVI variations at selected latitudes and on the global scale. The topological Pompeiu–Hausdorff metric was introduced as a measure and used to visualize the variations on UVI maps. This metric, tolerant to small positions errors, also cancels the errors which come from those in positioning satellites, blank regions caused by the satellite motion or clouds. The feed forward, multilayered supervised artificial neural network dedicated to the reconstruction of world maps of erythemal Ultraviolet index (UV index) was constructed and trained using three different sets of data selected from 1978 to 2005. A combined analysis made using Manhattan, Euclidean, Bhattacharyya, Hellinger and topological Pompeiu–Hausdorff metrics has revealed large unconnected and inhomogeneous areas of high variability in UVI maps. The modeling of the long term variation in UVI during the whole sun activity cycle helped to understand trends and predict the direction of future variations in UV radiation level. The quality of prediction was evaluated using a newly proposed approach based on Pompeiu–Hausdorff metric.

      PubDate: 2017-07-08T07:35:38Z
      DOI: 10.1016/j.ast.2017.06.017
      Issue No: Vol. 69 (2017)
       
  • Wing/canard interference of a close-coupled canard configuration in static
           ground effect
    • Authors: Yunpeng Qin; Peiqing Liu; Qiulin Qu; Tianxiang Hu
      Pages: 60 - 75
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Yunpeng Qin, Peiqing Liu, Qiulin Qu, Tianxiang Hu
      The aerodynamics and flow physics of a close-coupled canard configuration W40C60 (the sweep angles of the wing and canard are 40° and 60°, respectively) with sharp leading edge at the angle of attack of 12.0° in static ground effect are investigated by the Delayed Detached Eddy Simulation grounded on Spalart–Allmaras turbulence model. With the ride height decreasing, the lift, drag, nose-down pitching moment and lift to drag ratio of W40C60 increase nonlinearly. In the unbounded flow field, both the canard lift increment and the wing lift decrement due to Wing/Canard Interference (WCI) stem mainly from the leeward surface. With the ride height decreasing, the canard lift increment due to WCI will increase and the wing lift decrement due to WCI will decrease, which is because both the canard and wing windward surface lift increments due to WCI increase significantly with the decreasing ride height. The windward surface lift behaviors are also interpreted as that the windward surface pressure increment of canard and wing of W40C60 due to ground effect is larger than that of the canard alone and the wing alone, respectively. This is because the WCI increases the effective chord length so that the effective dimensionless ride height of W40C60 is smaller than those of the canard alone and the wing alone at the same nominal dimensionless ride height.

      PubDate: 2017-07-08T07:35:38Z
      DOI: 10.1016/j.ast.2017.06.012
      Issue No: Vol. 69 (2017)
       
  • The research on active flow control method with vibration diaphragm on a
           NACA0012 airfoil at different stalled angles of attack
    • Authors: Guangqiang Di; Zhaochun Wu; Diangui Huang
      Pages: 76 - 86
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Guangqiang Di, Zhaochun Wu, Diangui Huang
      The flow control method with vibration diaphragm as a relatively new active flow control method has shown its great potential of improving flow field. A two-dimensional numerical computation for flow over an airfoil with vibration diaphragm is present at different stalled angles of attack and Re = 1.2 × 10 5 . The vibration diaphragm is placed at the suction side of the airfoil surface near the leading edge and the length of the vibration diaphragm's projection along the chord direction is 0.1c. The effects of the dependant parameters dimensionless amplitude and frequency and the optimum parameters varying with different stalled angles of attack are investigated through enormous simulation data. Numerical results show that the lift coefficient and the lift-to-drag ratio increase firstly with the growth of the dimensionless frequency and then decrease. There exists the optimum dimensionless amplitude to make the control method behave best. The maximum increment of lift coefficient occurs at the low dimensionless frequency near 0.5, whereas for the lift-to-drag ratio, the maximum increment is attained the value of dimensionless frequency ranging from 1 to 1.5 at 16 degree angle of attack, the greatest improvement of the lift-to-drag ratio occurs when the value of dimensionless amplitude and frequency are 0.015 and 1.4, the maximum percent improvement is 91.31%. The oscillation coefficient is found to be a critical parameter to affect the lift-to-drag ratio of the airfoil and there exits an optimum oscillation coefficient to obtain greatest improvement of lift-to-drag ratio. The optimum parameters of the control methods to achieve the highest lift-to-drag ratio vary with different stalled angles of attack, with the growth of the angles of attack, the optimum dimensionless amplitude increases, the optimum dimensionless frequency decreases firstly and then keep the certain value 1.1 and the oscillation coefficient fluctuates weakly in the range of 1.15–1.3.

      PubDate: 2017-07-08T07:35:38Z
      DOI: 10.1016/j.ast.2017.06.020
      Issue No: Vol. 69 (2017)
       
  • Minimum time state consensus for cooperative attack of multi-missile
           systems
    • Authors: Xing Liu; Lei Liu; Yongji Wang
      Pages: 87 - 96
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Xing Liu, Lei Liu, Yongji Wang
      This paper considers the cooperative attack with multiple missiles on a stationary target and a two-step procedure is proposed. First the states of all missiles are guided to achieve minimum time consensus, and then, by using the proportional navigation guidance law with identical navigation gain each missile arrives at the target simultaneously or sequentially. Among which, the strategy to realize state consensus in minimum time is the focus of the issue. In the paper the coordination algorithms are developed based on bang–bang control strategy due to its simply structure, subsequently, it is proved that the time optimal consensus problem can be transformed into a parameter optimization problem. Besides, the proposed schemes are able to significantly reduce the number of parameters to be optimized and finally solve the problem with little computation cost. Different from the impact time control methods, the strategy for state consensus does not demand the information of time-to-go. Meanwhile only the initial values of missiles' states are required for the coordination algorithms which lead to less communication burden. Two different examples are provided to demonstrate the validity and efficiency of our proposed strategy.

      PubDate: 2017-07-08T07:35:38Z
      DOI: 10.1016/j.ast.2017.06.016
      Issue No: Vol. 69 (2017)
       
  • Analysis of the Bauschinger effect on a multilayer helicopter blade by
           XFEM simulation
    • Authors: Abdelkader Nour; Mohamed Tahar Gherbi; Imad Tawfiq
      Pages: 97 - 113
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Abdelkader Nour, Mohamed Tahar Gherbi, Imad Tawfiq
      Two major helicopter blade structural defects may disturb flight stability before crashes: i.e. debonding of the isotropic skin enveloping the orthotropic materials of the leading edge (UD glass – epoxy, aluminum honeycomb core) and cracking of the lower and upper surface shields. During beats, the thin metal skin of the leading edge is subjected to tensile stresses followed by compression stresses, capable of causing the Bauschinger effect, defined as a reduction of the elastic limit. Thus the purpose of this study is to present the dynamic behavior of a composite helicopter blade based on the Westergaard formulation of crack problems and a simulation using the extended finite element method (XFEM). This is followed by a comprehensive discussion on near crack tip fields for a helicopter blade composed of orthotropic materials, in order to develop the necessary enrichment functions for the XFEM formulation. Finally, several numerical simulations are provided to illustrate the validity, robustness and efficiency of the approach proposed to evaluate mode I stress intensity factors and J integrals in composites. The study of the transient behavior allows determining the vibration responses due to unbalance and different excitation modes.

      PubDate: 2017-07-08T07:35:38Z
      DOI: 10.1016/j.ast.2017.05.039
      Issue No: Vol. 69 (2017)
       
  • A coupled dynamic loads analysis of satellites with an enhanced
           Craig–Bampton approach
    • Authors: Jae Hyuk Lim; Do-Soon Hwang; Kyoung-Won Kim; Geun Ho Lee; Jin-Gyun Kim
      Pages: 114 - 122
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Jae Hyuk Lim, Do-Soon Hwang, Kyoung-Won Kim, Geun Ho Lee, Jin-Gyun Kim
      In this work, we conducted a coupled dynamic loads analysis (CDLA) of satellites with an enhanced Craig–Bampton (ECB) approach to predict maximum response (acceleration, displacement, and stress). The satellite was subjected to a relatively high frequency launch vehicle (LV) interface load ( 20 – 50 Hz) when it was launched by multiple satellite launcher or experienced the combustion instability caused by LV instead of a typical low frequency LV interface load ( 0 – 10 Hz). To minimize the error caused by mode truncation, ECB-like formulation, which considers the effect of residual modes, is employed and computes the maximum response of the given dynamic system. By using this method, we found that the response by the ECB model is more accurate and efficient over the classical Craig–Bampton (CB) model due to the enhanced transformation matrix from being subjected to an unexpected high frequency LV load. To demonstrate this performance, we solved several benchmark problems associated with CDLA.

      PubDate: 2017-07-08T07:35:38Z
      DOI: 10.1016/j.ast.2017.06.023
      Issue No: Vol. 69 (2017)
       
  • Detached-eddy simulation of flow past a pitching NACA 0015 airfoil with
           pulsed actuation
    • Authors: Liang Wang; Song Fu
      Pages: 123 - 135
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Liang Wang, Song Fu
      This study conducted Detached-Eddy Simulations (DES) of actively controlled flow over a 0.35 m chord NACA0015 airfoil at an incidence angle of 11° and a chord Reynolds number of 1 million. The uncontrolled, natural flow were simulated by using DES-type methods, with a comparison of different underlying RANS models and subgrid-scale stress models in LES mode. Results from these computations were compared with experimental observations, enabling their reliable assessment through the detailed investigation of the Reynolds stresses as well as the separation and reattachment. It was found that among all five DES-type methods, only the Spalart–Allmaras-based Improved Delayed DES (IDDES-SA) captured the separation point as measured in the experiments. The classical vortex-shedding and the shear-layer flapping modes for airfoil flows with shallow separation were also extracted from the IDDES-SA results by using Dynamic Mode Decomposition. With better understanding of unsteady flow features, effective control practices were illustrated. The pulsed blowing actuation was adopted according to the experimental settings. The flow-field around jet orifices was resolved, instead of the use of actuation boundary conditions. It was found that for all actuation frequencies investigated in this article, the saturation of lift-to-drag ratio was yielded already at intermediate momentum coefficients, two-fifths of the actuation amplitude used in the experiment; the optimal actuation frequency was 0.6 among all cases, consistent with the dominant frequency of the baseline flow. The suppression of separation bubble led to a maximum lift-to-drag ratio enhancement of 194%, as well as a sharp decrease of all Reynolds stress components. To further reduce the strong unsteadiness introduced by excitation, a phase shift among jet orifices was applied and evaluated. The pulsed blowing with the jet orifices in an anti-phased manner was found to be very effective to damp the fluctuations of the lift around its mean value, though it led to a small decrease in mean lift.

      PubDate: 2017-07-08T07:35:38Z
      DOI: 10.1016/j.ast.2017.06.002
      Issue No: Vol. 69 (2017)
       
  • Free vibration analysis of deep doubly curved open shells using the Ritz
           method
    • Authors: K. Malekzadeh Fard; A.M. Baghestani
      Pages: 136 - 148
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): K. Malekzadeh Fard, A.M. Baghestani
      This paper develops a unified semi-analytical method for the free vibration analysis of moderately thick doubly curved open shells with arbitrary geometry and classic boundary conditions. The only restriction on the shell's geometry is that boundaries are being coincided by the principal curvature lines of the shell. The formulation is based on the first order shear deformation theory by considering effects of curvature in the evaluation of stress resultants. Differential geometry method is used to represent the arbitrary shape of the middle surface of the shell. The Ritz method with algebraic polynomials as trial functions is employed to obtain the natural frequencies and mode shapes of the shell. To demonstrate the efficiency and accuracy of the solution, convergence and comparison studies are carried out for a cantilevered shallow shell and a parabolic panel. Furthermore, a variety of new vibration results including frequencies and mode shapes of ellipsoid and Enneper panels with various boundary conditions are presented which may be used as benchmark results for future studies.

      PubDate: 2017-07-08T07:35:38Z
      DOI: 10.1016/j.ast.2017.06.021
      Issue No: Vol. 69 (2017)
       
  • Automatic carrier landing system based on active disturbance rejection
           control with a novel parameters optimizer
    • Authors: Yue Yu; Honglun Wang; Na Li; Zikang Su; Jianfa Wu
      Pages: 149 - 160
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Yue Yu, Honglun Wang, Na Li, Zikang Su, Jianfa Wu
      This paper proposes an active disturbance rejection control (ADRC) scheme for automatic carrier landing system (ACLS) in final approach. To track desired touchdown point (DTP) altitude in the presence of carrier air wake turbulence and deck motion, based on the estimation and compensation of internal dynamics and external disturbances by extended state observer (ESO), outer-loop altitude controller and inner-loop attitude controllers are designed via ADRC. Moreover, tracking differentiator-based deck motion compensation (TD-DMC) is designed to eliminate the inherent phase lag in ACLS. In addition, controller parameters are optimized via a novel Levy flight based whale optimization algorithm (LWOA). Finally, comparative simulations demonstrate that the proposed ADRC-based ACLS has better tracking performance and robustness compared to conventional ACLS.

      PubDate: 2017-07-08T07:35:38Z
      DOI: 10.1016/j.ast.2017.06.026
      Issue No: Vol. 69 (2017)
       
  • Experimental and numerical studies of ammonium dinitramide based liquid
           propellant combustion in space thruster
    • Authors: Liyue Jing; Xiaoqing You; Jialong Huo; Min Zhu; Zhaopu Yao
      Pages: 161 - 170
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Liyue Jing, Xiaoqing You, Jialong Huo, Min Zhu, Zhaopu Yao
      In this paper, the combustion process of liquid propellant ammonium dinitramide (ADN)-methanol aqueous solution in a small space thruster is investigated experimentally and numerically. The phase Doppler anemometer measurement is used to investigate the injection process and the results are used as the liquid boundary condition in the simulation to minimize uncertainties. Hot fire tests have also been operated to estimate the performance of the thruster. To simulate the complicated processes in the thruster, a modified multi-component droplet model is employed to simulate the evaporation process considering the interaction between the liquid droplet and the porous media. A non-equilibrium model for the porous media is used to describe the heat transfer in the catalyst bed. A reduced chemical mechanism containing 18 species and 40 reactions is used to simulate the reactions of gas-phase ADN and methanol. The results show that the decomposition of ADN and the oxidization of methanol do not happen synchronously in the chamber. The decomposition of ADN takes place near the inlet while methanol is oxidized downstream of the porous media. The establishment of pressure in the thruster depends on the evaporation and reaction processes and the temperature changes relatively slowly because the porous media increases the thermal inertia of the whole system.

      PubDate: 2017-07-08T07:35:38Z
      DOI: 10.1016/j.ast.2017.05.035
      Issue No: Vol. 69 (2017)
       
  • Prescribed performance interceptor guidance with terminal line of sight
           angle constraint accounting for missile autopilot lag
    • Authors: Shi Lyu; Xiaodong Yan; Shuo Tang
      Pages: 171 - 180
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Shi Lyu, Xiaodong Yan, Shuo Tang
      A prescribed performance guidance law during the terminal homing phase is proposed to intercept a non-cooperative maneuvering target in this paper. First, on the basis of sliding mode control, a prescribed performance control method based on a revised prescribed performance function is proposed to drive the sliding mode variable to zero. It leads to smooth guidance commands to fulfill the terminal line of sight angle constraint. Then, taking the autopilot's dynamics and its uncertainties into account, a robust controller is designed using dynamic surface control, sliding mode control and inertial delay control, which guarantees the reference guidance commands to be precisely tracked. The highlights of the proposed guidance law are: 1) the transient performance of guidance commands is improved, so that excessive large changes are avoided in the initial phase, 2) parameters that dominant the convergence of the predetermined sliding mode variable can be analytically determined based on the predesigned terminal tolerance, it is more convenient to achieve the prescribed convergence, 3) although uncertainties are existing in the dynamics of missile autopilot, the proposed guidance law could guarantee the terminal interception accuracy. All of the improvements are shown in numerical simulation results.

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.06.022
      Issue No: Vol. 69 (2017)
       
  • Fruit fly impact on an aerodynamic surface: Types of outcomes and residue
           components
    • Authors: K. Ghokulla Krishnan; Athanasios Milionis; Foffo Tetteh; Eric Loth
      Pages: 181 - 192
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): K. Ghokulla Krishnan, Athanasios Milionis, Foffo Tetteh, Eric Loth
      Leading edge contamination on aircraft wings and wind turbine blades can occur through the accumulation of insect residues, which can then increase drag by causing an earlier transition of the boundary layer from laminar to turbulence. To investigate the mechanisms of residue adherence and composition, this study focuses on the impact dynamics of insects striking an airfoil with a circular leading edge placed in a wind tunnel at a wind speed of about 100 mph. To mimic in-flight conditions, live flightless fruit flies (Drosophila melanogaster) were injected into the wind tunnel sufficiently upstream such that they reached the test section air-flow speed prior to impact on the airfoil. The aerodynamic surface had a leading edge radius of 3.8 cm and was tested with coatings of various surface wettability, ranging from hydrophilic to superhydrophobic. Based on previous studies and present high-speed imaging and surface imaging, five types of insect outcomes were defined (roughly in order of increasing impact speed): 1) insect bounce without rupture and no residue, 2) insect burst with release of internal fluid with adherence of full exoskeleton, 3) insect burst with release of internal fluid with little or no exoskeleton adherence, 4) disintegration of insect yielding residue of many pieces of exoskeleton, and 5) insect burst with neither fluid nor exoskeleton residue. The fifth outcome generally occurred for a superhydrophobic surface developed in this study. When insect residue did occur on a surface, it included up to three distinct components (in order of decreasing residue heights): exoskeleton pieces, yellow hemolymph from the insect abdomen and thorax, and red fluid from the insect head. Surfaces with lower surface wettability generally yielded reduced insect hemolymph residue area per insect release. In particular, a superhydrophobic coating yielded the lowest residue area and no exoskeleton residue, while the aluminum surface resulted in the highest residue area and several exoskeletons.

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.06.006
      Issue No: Vol. 69 (2017)
       
  • An experimental study on the detonability of gaseous hydrocarbon
           fuel–oxygen mixtures in narrow channels
    • Authors: Bo Zhang; Hong Liu; Cheng Wang; Bingjian Yan
      Pages: 193 - 200
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Bo Zhang, Hong Liu, Cheng Wang, Bingjian Yan
      This study was performed to address the detonability related to gaseous hydrocarbon fuel–oxygen mixtures (i.e., CH4–2O2, C2H6–3.5O2 and C3H8–5O2) in different ducts (36-mm circular tube and annular channel heights with 2-mm, 4.5-mm and 7-mm gaps). The results show that detonation can achieve self-sustained propagation with a steady velocity because the conditions are within the detonability in C1–C3 alkanes/oxygen mixtures; the velocity decreases as the detonation transmits into the annular channel due to increased heat and momentum losses from the wall. A modified theoretical model is proposed to predict the detonation velocity deficit for different size channels. Through a comparison with the experimental results, this model was determined to be suitable for predicting the velocity deficit in C1–C3 alkane fuel with oxygen mixtures within reasonable accuracy. Both experimental and theoretical predicted data indicate that velocity deficit is more significant in the smaller channel gap, which verifies that losses are more prominent in the narrower channel. Furthermore, the detonation cellular structure from the smoked foil was measured to analyze the propagation mechanism. The results show detonation has a single-headed spinning structure when detonability is approached. The onset of single-headed spinning detonation of CH4–2O2, C2H6–3.5O2 and C3H8–5O2 in a 36-mm circular tube occurs from p 0 = 3 – 7  kPa , 4.2–5 kPa and 3.5–3.6 kPa, respectively. This suggests the pressure range of the single-headed spinning phenomenon is narrower for hydrocarbon fuels with more carbon atoms.

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.06.032
      Issue No: Vol. 69 (2017)
       
  • Ballistic impact response of fiber–metal laminates and monolithic metal
           plates consisting of different aluminum alloys
    • Authors: George S.E. Bikakis; Christos D. Dimou; Emilios P. Sideridis
      Pages: 201 - 208
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): George S.E. Bikakis, Christos D. Dimou, Emilios P. Sideridis
      In this article, the ballistic impact response of square clamped fiber–metal laminates and monolithic plates consisting of different aluminum alloys is investigated using the ANSYS LS-DYNA explicit nonlinear analysis software. The panels are subjected to central normal high velocity ballistic impact by a cylindrical projectile. The implemented finite element models have been validated by comparison with published experimental data concerning GLARE 5 and monolithic 2024-T3 aluminum plates. Using the validated models, the influence of the mechanical properties of the constituent aluminum alloy on the ballistic resistance of the fiber–metal laminates and the monolithic plates is studied. Apart from 2024-T3, the aluminum alloys 2024-T351, 2024-O, 6061-T6, 7039 and 7075-T6 are considered. It is found that the ballistic limits of the panels can be substantially affected by the constituent aluminum alloy. The 7075-T6 aluminum alloy offers the highest ballistic resistance whereas 2024-O aluminum alloy offers the lowest ballistic resistance.

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.06.028
      Issue No: Vol. 69 (2017)
       
  • Optimal short-range rendezvous using on–off constant thrust
    • Authors: Gang Zhang; Dong Ye
      Pages: 209 - 217
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Gang Zhang, Dong Ye
      A control parameter direct optimization method for the optimal short-range elliptic orbit rendezvous problem using on–off constant thrust is proposed. This method is based on analytical state propagation expressions for linear relative motion under on–off constant control acceleration. This avoids numerical integration for the orbit dynamic equations. Normalized optimization variables are introduced to replace switching times. Then this problem is transformed into a nonlinear programming problem with bound constraints on the optimization variables and terminal equality constraints. The along-track and cross-track thrusts are used for the in-plane and out-of-plane motions, respectively. Both the minimum-fuel and minimum-time solutions are obtained by using the Matlab function fmincon. Numerical examples are provided to verify the proposed method. The results indicate that the proposed method is accurate and fast.

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.06.029
      Issue No: Vol. 69 (2017)
       
  • Regressor time-shifting to identify longitudinal stability and control
           derivatives of the Jetstream 3102
    • Authors: Sezsy Yusuf; Mudassir Lone; Alastair Cooke; Nicholas Lawson
      Pages: 218 - 225
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Sezsy Yusuf, Mudassir Lone, Alastair Cooke, Nicholas Lawson
      The Jetstream 31 G-NFLA aircraft is used as a national flying laboratory test vehicle for flight dynamics research and teaching purposes. It has been the subject of much theoretical and experimental modelling and therefore, the need for generating validation data through flight testing is critical. In this paper, the aircraft's short period pitch oscillation mode characteristics are identified using data from sixteen flight tests. An identification procedure based on the least squares method and reduced order state-space model is used and the need for pre-processing regressors due to the effects of sensor location and instrumentation delays is highlighted. It has been shown that time-shifting the regressors based on relative locations of the angle of attack vanes and the inertial measurement unit results in significant reductions in uncertainty bounds of the estimated aeroderivatives and also a model that provides a closer match to flight test data. The estimated models are validated using separate flight test data and the variations in aeroderivatives over a range of airspeeds and centre of gravity positions are also presented.

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.06.003
      Issue No: Vol. 69 (2017)
       
  • A hybrid fuzzy method for performance evaluation of fusion algorithms for
           integrated navigation system
    • Authors: Xinlong Wang; Xun Wang; Jiafang Zhu; Feng Li; Qunsheng Li; Huan Che
      Pages: 226 - 235
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Xinlong Wang, Xun Wang, Jiafang Zhu, Feng Li, Qunsheng Li, Huan Che
      Aiming at the problem that traditional evaluation methods based on analytic hierarchy process (AHP) are influenced by subjectivity, this paper proposes an efficacious evaluation method which combines fuzzy logarithmic least square AHP method (fuzzy LLSM) with fuzzy comprehensive evaluation (FCE) method. Fuzzy LLSM is applied to derive the weights and FCE method is for comprehensive evaluation. Then FCE method would provide evaluation results through synthesizing the derived weight vector and membership matrix by a fuzzy operator based upon weighted average. Considering that the membership matrix requires a crisp weight vector to implement synthesis, but the derived weights have the problems of non-uniqueness and fuzziness, so we deduce the constraints to ensure the uniqueness of weights. And defuzzification of fuzzy weights is realized by using the CFCS (Converting Fuzzy numbers into Crisp Scores) method. As a result, the unique and defuzzificated weights are available to synthesis for FCE method directly. Taking the performance evaluation of SINS/Land-based/GPS integrated navigation system for a numerical example, some simulations have been carried out and we draw the conclusion that, the proposed fuzzy LLSM AHP-FCE method is superior to the existing and representative methods when applied to performance evaluation of fusion algorithm for integrated navigation system.

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.06.027
      Issue No: Vol. 69 (2017)
       
  • Line-of-sight nonlinear model predictive control for autonomous rendezvous
           in elliptical orbit
    • Authors: Peng Li; Zheng H. Zhu
      Pages: 236 - 243
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Peng Li, Zheng H. Zhu
      The paper investigates the trajectory planning and control of autonomous spacecraft rendezvous in the orbital plane with line-of-sight dynamics. The control problem, based on nonlinear model predictive control, is formulated in terms of line-of-sight range and azimuth angle. The state feedback with measurement uncertainties is introduced to form a closed-loop optimal control problem by integration of receding horizon strategy. Furthermore, the control input increment instead of total control input is considered in the cost function to generate a smooth transient response. The formulated nonlinear optimal control problem is then transformed into convex quadratic programming problems over the predictive horizon, leading to a computationally efficient algorithm implementable for spacecraft. The numerical results show that the newly proposed line-of-sight nonlinear model predictive control scheme is able to effectively generate optimized approach trajectories with satisfactory control accuracy and the proposed method is insensitive to the measurement uncertainties.

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.06.030
      Issue No: Vol. 69 (2017)
       
  • Drag reduction of supersonic blunt bodies using opposing jet and nozzle
           geometric variations
    • Authors: Atiqa Bibi; Adnan Maqsood; Salma Sherbaz; Laurent Dala
      Pages: 244 - 256
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Atiqa Bibi, Adnan Maqsood, Salma Sherbaz, Laurent Dala
      Passive and active flow control methods are used to manipulate flow fields to reduce acoustic signature, aerodynamic drag and heating experienced by blunt bodies flying at supersonic and hypersonic speeds. This paper investigate the use of active opposing jet concept in combination with geometric variations of the opposing jet nozzle to alleviate high wave drag formation. A numerical study is conducted to observe the effects of simple jet as well as jet emanating from a divergent nozzle located at the nose of a blunt hemispherical body. An initial discussion is presented of the complex shock wave pattern flow physics occurring when opposing jet ejected from a nozzle under various operating conditions interacts with the free stream flow. The complex flow physics that include long penetration and short penetration mode is studied in conjunction with effect on drag. The numerical setup consists of supersonic free stream flow interacting with an opposing sonic jet under varying pressure ratios. Initial computational results are validated by identifying prominent flow features as well as comparing available experimental data of surface pressure distributions. Preliminary validation is followed by the introduction of a divergent nozzle in the blunt body nose region. A series of numerical iterations are performed by varying nozzle geometric parameters that include nozzle divergent angle and nozzle length for a certain jet pressure ratio. Long penetration mode, short penetration mode as well as flow separations are captured accurately during the analysis. The results show a considerable reduction in drag by the use of a divergent nozzle. Specifically, 46% and 56% reduction in drag coefficient is achieved at pressure ratio of 0.6 and 0.8 respectively in the divergent nozzle cases as compared to the simple blunt body without any nozzle.

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.06.007
      Issue No: Vol. 69 (2017)
       
  • Effects of axisymmetric arc-shaped slot casing treatment on partial surge
           initiated instability in a transonic axial flow compressor
    • Authors: Tianyu Pan; Qiushi Li; Wei Yuan; Hanan Lu
      Pages: 257 - 268
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Tianyu Pan, Qiushi Li, Wei Yuan, Hanan Lu
      Instability initiated by rotating stall and surge limits the normal operating range of compressors, and seriously deteriorates the efficiency of gas-turbines. Partial surge is a new type of instability inception observed in a transonic axial flow compressor; it occurs in the form of axisymmetric low-frequency disturbances localized in the hub region and finally grows into rotating stall. For energy saving purposes, it is necessary to enhance the operating margin or stall margin of compressors. In this paper, a new design of casing treatment (axisymmetric arc-shaped slot casing treatment) is investigated to enhance the stall margin of a transonic compressor whose instability is initiated by partial surge. Both compressor performance and instability evolution before and after treatment are analyzed. The stall margin is successfully enhanced by 19.88% with the casing treatment, but the total pressure ratio only drops by 0.3% and the adiabatic efficiency does not quite change (increases by 0.15%), compared with the original solid wall case. The results of instability evolution present that partial surge occurs at nearly the same mass flow rate as the stall point of the solid wall case. As the compressor is further throttled, partial surge disappears. Then, rotating stall cells suddenly appear and trigger the formation of partial surge. In the presence of rotating stall cells and partial surge, the compressor suddenly and substantially turns into the final instability (substantial drop of compressor performance). The reasons for why the stall margin can be enhanced with this casing treatment are discussed, and the functions of the casing treatment are also discussed.

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.05.036
      Issue No: Vol. 69 (2017)
       
  • Multi objective optimization of sound transmission across laminated
           composite cylindrical shell lined with porous core investigating
           Non-dominated Sorting Genetic Algorithm
    • Authors: R. Talebitooti; H.D. Gohari; M.R. Zarastvand
      Pages: 269 - 280
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): R. Talebitooti, H.D. Gohari, M.R. Zarastvand
      The current formulation applies Non-dominated Sorting Genetic Algorithm (NSGA-II) as well as First-order Shear Deformation Theory (FSDT) to optimize Sound Transmission Loss (STL) of the laminated composite cylindrical shell lined with a porous material subjected to a plane sound wave. Therefore, in the first part of the paper, the Extended Full method [29] is employed to provide an exact solution based on three dimensional elasticity theory as well as investigating the well-known Helmholtz decomposition to present fluid pressure, the displacement fields and the solid stresses. Subsequently, some configurations are brought up to illustrate the accuracy of the present results. Furthermore, this paper also clarifies the importance of applying porous layer by demonstrating the direct influence between porous layer thicknesses and STL of the structure particularly in high frequency region. Consequently, in the second part of the paper the NSGA-II method is applied to multi objective optimize of sound transmission into such structure taking account the appropriate Pareto front which result in substantial improvement on the performance of the system based on minimizing the weight as well as maximizing sound transmission. Therefore, this procedure is followed by considering suitable design variables to designate what combination of design variables could result in a composite shell satisfying the sound insulation.

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.06.008
      Issue No: Vol. 69 (2017)
       
  • Influence of leading edge tubercles on aerodynamic characteristics of a
           high aspect-ratio UAV
    • Authors: S. Sudhakar; N. Karthikeyan; L. Venkatakrishnan
      Pages: 281 - 289
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): S. Sudhakar, N. Karthikeyan, L. Venkatakrishnan
      An experimental investigation was carried out to study the aerodynamic performance of a typical UAV whose wings were modified to incorporate tubercles on the leading edge. The aerodynamic characteristics of three configurations: a baseline (without leading edge tubercles), one with tubercles of constant wavelength and amplitude along the span (Case I) and the third with tubercles of varying amplitude and wavelength along the span (Case II) were evaluated using force measurements and surface flow visualization at Reynolds numbers ( Re c ¯ ) of 0.18 million and 0.27 million. At Re c ¯ = 0.18 million, the wings with tubercles exhibited increased lift, stall angle and reduced drag as compared to the baseline over the range of incidences studied. Further, wing with tubercles significantly improved the aerodynamic efficiency ( C L / C D ) (up to 25%). At Re c ¯ = 0.27 million, both the baseline and the modified wings exhibited identical lift characteristics, but the former had a higher drag. At both Reynolds numbers, the modified wings did not exhibit the hysteresis present in the baseline case. Additionally, the modified wings exhibited stable pitching moment characteristics even in the post stall regime. The Case II wing outperformed both the baseline and Case I wings. The results show that tubercles on the leading edge have beneficial effects especially when UAVs encounter sudden vertical gusts during operation.

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.06.031
      Issue No: Vol. 69 (2017)
       
  • The development of a new model to simulate the dispersion of rocket
           exhaust clouds
    • Authors: Erick Giovani Sperandio Nascimento; Davidson Martins Moreira; Taciana Toledo de Almeida Albuquerque
      Pages: 298 - 312
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Erick Giovani Sperandio Nascimento, Davidson Martins Moreira, Taciana Toledo de Almeida Albuquerque
      This study presents the development of a new model named MSRED, which was designed to simulate the formation, rise, expansion, stabilisation and dispersion of rocket exhaust clouds for short-range assessment, using a three-dimensional semi-analytical solution of the advection–diffusion equation based on the ADMM method. For long-range modelling, the MSRED was built to generate a ready-to-use initial conditions file to be input to the CMAQ model, as it represents the state-of-the-art in regional and chemical transport air quality modelling. Simulations and analysis were carried out in order to evaluate the application of this integrated modelling system for different rocket launch cases and atmospheric conditions, for the Alcantara Launching Center (ALC, the Brazilian gate to the space) region. This hybrid, modern and multidisciplinary system is the basis of a modelling framework that will be employed at ALC for pre- and post-launching simulations of the environmental effects of rocket operations.

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.06.034
      Issue No: Vol. 69 (2017)
       
  • Supersonic flow control via plasma, electric and magnetic impacts
    • Authors: T.A. Lapushkina; A.V. Erofeev
      Pages: 313 - 320
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): T.A. Lapushkina, A.V. Erofeev
      The possibility to control the shock wave configuration by plasmagasdynamic (PGD), electrogasdynamic (EGD) and magnetohydrodynamic (MHD) methods is presented. In particular, the effects of gas discharges with different parameters on the position and shift of a bow shock wave in the supersonic flow of ionized xenon past a semi-cylinder body are considered. In the plasmagasdynamic control method a discharge creates the strongly non-equilibrium plasma in the flow ahead of the body. In experiments it has been shown that the change in the bow shock-wave position depends on the degree of plasma non-equilibrium. In the EGD and MHD methods, a discharge was organized at the near surface area of the nose part of the body. In these cases the changes in the bow shock wave positions were achieved by changing the discharge intensity (EGD method) or by applying an external magnetic field (MHD method).

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.06.033
      Issue No: Vol. 69 (2017)
       
  • Free vibration of conical shells with intermediate ring support
    • Authors: H. Bagheri; Y. Kiani; M.R. Eslami
      Pages: 321 - 332
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): H. Bagheri, Y. Kiani, M.R. Eslami
      Free vibration behaviour of a shear deformable conical shell with intermediate ring support is analysed in this research. It is assumed that the conical shell is made from a linearly elastic isotropic homogeneous material. To capture the through-the-thickness shear deformations and rotary inertia effects, first order shear deformation theory of shells accompanied with the Donnell type of kinematic assumptions are adopted to establish the general equations of motion and the associated boundary conditions with the aid of Hamilton's principle. The resulting system of equations are discreted using the semi-analytical generalised differential quadratures (GDQ) method. The shell is divided into two sections, where the continuity conditions are satisfied at the ring position. Considering various types of boundary conditions for the shell ends and continuity conditions at the ring position, an eigenvalue problem is established to examine the natural frequencies of the shell reinforced with an intermediate ring support. After proving the efficiency and validity of the present method for the case of thin isotropic homogeneous cylindrical shell with intermediate ring support, parametric studies are carried out for the case of shear deformable conical shells with intermediate ring support.

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.06.037
      Issue No: Vol. 69 (2017)
       
  • Performance analysis of realistic true proportional navigation against
           maneuvering targets using Lyapunov-like approach
    • Authors: Ke-Bo Li; Wen-Shan Su; Lei Chen
      Pages: 333 - 341
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Ke-Bo Li, Wen-Shan Su, Lei Chen
      The realistic true proportional navigation (RTPN) is a variant of the true proportional navigation (TPN) guidance law for mathematical tractability. Although the performance of RTPN against nonmaneuvering targets or maneuvering targets with specific acceleration forms has been widely analyzed before, its performance against arbitrarily maneuvering targets has still not been explored. In this paper, using the Lyapunov-like approach, the performance of RTPN against maneuvering targets, whose magnitude is arbitrary but upper-bounded and direction is vertical to the line-of-sight (LOS), is well studied. The upper bounds of the LOS rate and commanded acceleration of RTPN are obtained, and the capture region is also presented. The nonlinear relative dynamics between the missile and target is taken into full account. Finally, the proposed theoretical findings are demonstrated by numerical simulation examples.

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.06.036
      Issue No: Vol. 69 (2017)
       
  • Canard–wing interference effects on the flight characteristics of a
           transonic passenger aircraft
    • Authors: Mehdi Ghoreyshi; Ryan Darragh; Sean Harrison; Andrew J. Lofthouse; Peter E. Hamlington
      Pages: 342 - 356
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Mehdi Ghoreyshi, Ryan Darragh, Sean Harrison, Andrew J. Lofthouse, Peter E. Hamlington
      Effects of canard–wing interference on the flight characteristics of a civilian transonic cruiser aircraft are examined using computational fluid dynamics (CFD) simulations, a vortex lattice solver, and wind tunnel measurements. These data sources are used to generate reduced-order aerodynamic models in the form of look-up tables that give longitudinal and lateral force and moment coefficients for different combinations of angle of attack, Mach number, side-slip angle, and canard deflection angle. Flight characteristics from CFD simulations and the vortex lattice solver are compared with wind tunnel measurements in order to determine model accuracy for both static and dynamic flight conditions. Static cases are examined at a Mach number of 0.1 for two different canard positions using an overset grid approach. Cases considered include canard deflections of − 30 ∘ , − 10 ∘ , 0 ∘ , and 10 ∘ at angles of attack ranging from − 4 ∘ to 30 ∘ and for sideslip angles of − 6 ∘ and 6 ∘ . Dynamic cases are examined for aircraft oscillations about mean angles of attack of 0 ∘ to 10 ∘ , with a motion frequency of 1 Hz and an amplitude of 0.5 ∘ . The results indicate that both static and dynamic aerodynamic predictions from CFD simulations are in good agreement with experiments over the range of conditions considered. The vortex lattice solver, by contrast, cannot predict vortical flows formed over the wing and canard surfaces, resulting in poorer agreement with experimental data. The CFD-based reduced order aerodynamic model is then used to investigate trim settings and handling qualities of two different canard designs. Results show that positioning the canard surface of the transonic cruiser closer to the wing requires less canard deflection and thrust force to trim the aircraft.

      PubDate: 2017-07-20T17:32:53Z
      DOI: 10.1016/j.ast.2017.06.024
      Issue No: Vol. 69 (2017)
       
  • Analytical stiffness model of a fluid-filled U-shaped bellows based
           three-parameter fluid damper for micro-vibration suppression
    • Authors: Xiuchang Huang; Zhenguo Zhang; Jingya Sun; Zhiyi Zhang; Hongxing Hua
      Pages: 357 - 369
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Xiuchang Huang, Zhenguo Zhang, Jingya Sun, Zhiyi Zhang, Hongxing Hua
      Bellows are widely employed to construct three-parameter fluid damper in application to on-orbit micro-vibration isolation thanks to its ability to provide accurate stiffness and deformation without dry friction. An analytical stiffness model is established to provide a designing method for a U-shaped bellows based three-parameter fluid damper, which considers coupling between bellows and fluid to account for fluid–structure interaction (FSI). Firstly, the stiffness and volume deformation for a U-shaped bellow under composite axial load and internal pressure are obtained based on the analytical model of a U-shaped bellow. Then, the FSI model of a three-parameter damper is established to obtain the output force and internal pressure under harmonic displacement input. The stiffness model employs expressions of volume deformation, the pressure equation and the continuity equation in the orifice to derive the coupling equation, and the force and pressure are obtained by solving the equation with the Laplace transform method. The stiffness model of the bellow is verified by a finite element model. The stiffness model of the U-shaped bellows based three-parameter damper is validated with a two-way FSI analysis carried out in ANSYS WORKBENCH. The results demonstrate that analytical prediction is in good agreement with numerical simulation with greatly enhanced efficiency.

      PubDate: 2017-07-27T17:45:11Z
      DOI: 10.1016/j.ast.2017.07.004
      Issue No: Vol. 69 (2017)
       
  • Numerical investigation of effects of angle-of-attack on a parachute-like
           two-body system
    • Authors: Xiaopeng Xue; Yoshiaki Nakamura; Koichi Mori; Chih-Yung Wen; He Jia
      Pages: 370 - 386
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Xiaopeng Xue, Yoshiaki Nakamura, Koichi Mori, Chih-Yung Wen, He Jia
      The supersonic flows around a typical parachute-like two-body system are numerically studied at a freestream Mach number of 2.0. Both rigid and flexible models, composed of a capsule and a canopy, are considered. The objective is to analyze the effects of angle of attack (AoA) on the unsteady flow produced by the parachute-like two-body system and the difference in flow behaviors between the rigid and flexible systems. The following two model configurations are examined for the rigid canopy case: (1) the canopy is connected to the capsule with a rigid rod and (2) the canopy is separate from the capsule. It is found that at a moderate capsule AoA, the most unstable flow field is generated in the interior of the canopy and the connecting rod has a significant effect on the flow field. For the flexible case, the supersonic flows over the model (2) configuration and the canopy alone are investigated. An area oscillation phenomenon is observed in the flexible canopy. When the capsule AoA is increased, the flexible canopy has greater deformation, which results in a lower drag coefficient. The effect of the canopy AoA is also examined for the flexible canopy alone. A small deformation in the canopy shape is observed.

      PubDate: 2017-07-27T17:45:11Z
      DOI: 10.1016/j.ast.2017.06.038
      Issue No: Vol. 69 (2017)
       
  • Accuracy improvement of second-order central scheme using smart
           post-process filter for hybrid RANS/LES method
    • Authors: Reza Pasandeh; Vahid Esfahanian
      Pages: 387 - 394
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Reza Pasandeh, Vahid Esfahanian
      The present research aims to propose a new approach to improve the performance of computational codes employing the RANS/LES technique with 2nd order central scheme. To accomplish this, an unsteady compressible 3D coupled RANS/LES solver using two-equation turbulence model is developed. A smart post-processing filter is also embedded as the dissipation term in the code to maintain both the stability and the accuracy. A predesign sensor that detects the amount and position of non-physical fluctuations in numerical solution, controls the smart post-processing filter. Detailed study is performed to investigate the performance of this sensor and filter. The methodology is validated against several experimental observations and numerical findings for compressible high-Reynolds flow regimes. The unsteady 3D flow over a wing with NACA 0015 section at high angle of attack is computed to evaluate the model performance. The results indicate that the proposed methodology shows promising accuracy for both steady and unsteady flow simulations, especially in high angles of attack, in which the accuracy of the other schemes is normally decreased considering the flow separation phenomena.

      PubDate: 2017-07-27T17:45:11Z
      DOI: 10.1016/j.ast.2017.06.035
      Issue No: Vol. 69 (2017)
       
  • Rarefied aerodynamics of a deployable re-entry capsule
    • Authors: Stefano Mungiguerra; Gennaro Zuppardi; Raffaele Savino
      Pages: 395 - 403
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Stefano Mungiguerra, Gennaro Zuppardi, Raffaele Savino
      Several research activities have been already carried out in the field of low-ballistic coefficient re-entry capsules based on deployable umbrella-like aero-shield. The flexible aero-shield, made of ceramic fabrics, acts both as an aero-brake and a Thermal Protection System (TPS), making possible to perform a re-entry from orbital or suborbital conditions with relatively low values of the aero-thermo-dynamic loads. Previous studies have already analyzed Aerodynamics of similar systems, identifying self-stabilizing configurations and creating a preliminary database of force and moment coefficients in different flight regimes. This work is intended to provide a systematic overview of the aerodynamic behavior of a deployable capsule in the rarefied regime, where the differences between the re-entry trajectories from Low-Earth-Orbit and suborbital flight conditions are more evident. Particular focus is given to the longitudinal stability analysis, which demonstrates that, as the continuum hypersonic regime approaches, the capsule could show a stable equilibrium condition in the unfavorable reverse attitude. This unwanted equilibrium condition could be counteracted by moving the center of gravity out of the symmetry axis.

      PubDate: 2017-07-27T17:45:11Z
      DOI: 10.1016/j.ast.2017.07.007
      Issue No: Vol. 69 (2017)
       
  • Analysis of the plastic zone under mixed mode fracture in bonded composite
           repair of aircraft structures
    • Authors: Wahid Oudad; Djamal Eddine Belhadri; Hamida Fekirini; Malika Khodja
      Pages: 404 - 411
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Wahid Oudad, Djamal Eddine Belhadri, Hamida Fekirini, Malika Khodja
      Material fracture by opening (mode I) is not the only failure criteria responsible for fracture propagation. Many industrial examples show the presence of mode II and mixed mode I + II. In the present work, numerical analyses of the three-dimensional and non-linear finite element method are used to estimate the performance of the bonded composite repair of metallic aircraft structures with a pre-existent damage by analyzing the plastic zone size ahead of repaired cracks under mixed mode loading, to assess the effect of the composite repair system on the plastic zone. The Von Mises stress is used to predict yielding of materials under this loading condition. The extension of the plastic zone, which takes place at the tip of a crack, strictly depends on many variables, such as the yield stress of the material, the loading conditions, the crack size and the thickness of the cracked component. The obtained results have demonstrated that the plastic zone ahead of the crack is significantly reduced by the presence of composite patch materials. Furthermore, parametric analysis has been carried out to evaluate the effect of lay-up and material system variation on the J integral.

      PubDate: 2017-07-27T17:45:11Z
      DOI: 10.1016/j.ast.2017.07.001
      Issue No: Vol. 69 (2017)
       
  • Finite element model updating of liquid rocket engine nozzle based on
           modal test results obtained from 3-D SLDV technique
    • Authors: Song Yan; Bin Li; Feng Li; Binchao Li
      Pages: 412 - 418
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Song Yan, Bin Li, Feng Li, Binchao Li
      In order to update the finite element model, the modal test results must be highly accurate since they are used as the basis. The major problems with traditional modal test method are limited measurement points and poor mode shape precision. In this paper, modal test based on 3-D Scanning Laser Doppler Vibrometry (SLDV) technique was carried out. High spatial resolution and accurate mode shapes were obtained, which is beneficial to subsequent correlation analysis and updating process. High order modal parameters were identified and more information can be added in the objective function. Due to the consistent coordinate system in modal test and finite element model, the measurement points and corresponding finite element nodes were easily matched in order to compare mode shapes. By means of a real liquid rocket engine nozzle, an integrated model updating process is presented from proper initial model, accurate modal test results, test/analysis correlation to automatic model updating. The single steps of detailed updating process are highlighted. The discrepancy between the finite element model predicted and the experiment measured modal parameters are minimized and satisfactory results were obtained.

      PubDate: 2017-07-27T17:45:11Z
      DOI: 10.1016/j.ast.2017.07.002
      Issue No: Vol. 69 (2017)
       
  • Deployment analysis for space cable net structures with varying topologies
           and parameters
    • Authors: Rui Nie; Baiyan He; Lianhong Zhang; Yonggang Fang
      Pages: 1 - 10
      Abstract: Publication date: September 2017
      Source:Aerospace Science and Technology, Volume 68
      Author(s): Rui Nie, Baiyan He, Lianhong Zhang, Yonggang Fang
      Cable net structures are widely used in space deployable devices. For truss-mesh reflector antennas, the cable net turns from a relaxed stage to a full tensioned state and forms a required functional surface during the deployment process. The deployment analysis of cable net structures is indispensable to the calculation of the deploying force, and meanwhile, it also provides valuable references for the cable net design. But unfortunately, at present there is still no effective way to analyze the deployment process of space cable net structures with varying topologies and parameters. In this paper, the parameterized deployment analysis for space cable net structures considering geometric nonlinearity, topological diversity and the cable's sag is presented. Firstly, the cable net is discretized into finite cable elements, and serial numbering rule is proposed to obtain the corresponding topological matrix. Then, governing equations are formulated and further assembled by matrix transformation theory, and trust-region algorithm is used to solve the system equations. In the calculating, the cable's stiffness is determined by its slack or tensional state, and the coupling between the deployment of trusses and the deformation of cable nets are considered by updating the coordinate values of boundary nodes in each time step. We use our method to analyze three case studies and the results agree with experiment data in previous literature. The elastic energies of cable nets during the deployment are calculated and the “self-stretching” process is discussed. The deployment analysis in this research is general for space cable net structures used in mesh reflector antennas.

      PubDate: 2017-05-20T16:24:05Z
      DOI: 10.1016/j.ast.2017.05.008
      Issue No: Vol. 68 (2017)
       
  • Extreme aircraft maneuver under sudden lateral CG movement: Modeling and
           control
    • Authors: Bijoy K. Mukherjee; Manoranjan Sinha
      Pages: 11 - 25
      Abstract: Publication date: September 2017
      Source:Aerospace Science and Technology, Volume 68
      Author(s): Bijoy K. Mukherjee, Manoranjan Sinha
      Hitherto unaddressed issue of six degree-of-freedom transient dynamics during asymmetric ejection of stores with finite velocity, onboard a combat aircraft, is addressed and modeled from the first principle. Further, the effect of asymmetric center-of-gravity shift, post ejection of the store, on some complex high angle-of-attack maneuvers such as cobra and Herbst is also investigated. It is shown that the performance of the maneuvers drastically deteriorates when carried out with controller designed for the pre-ejection symmetric c . g . based dynamics. In order to improve the deteriorated performance, two new control schemes based on the standard sliding mode technique are proposed. The first sliding control is designed based on a simple ad-hoc model for the asymmetric dynamics, whereas the states are propagated using the exact model developed. It is shown that using this scheme the lost maneuver performance can be reasonably recovered. The second control scheme is formulated using an accurate asymmetric dynamics. This proposed control scheme almost completely recovers the original maneuver performance.

      PubDate: 2017-05-20T16:24:05Z
      DOI: 10.1016/j.ast.2017.04.030
      Issue No: Vol. 68 (2017)
       
  • Aerodynamic shape optimization of a transonic fan by an adjoint-response
           surface method
    • Authors: Xiao Tang; Jiaqi Luo; Feng Liu
      Pages: 26 - 36
      Abstract: Publication date: September 2017
      Source:Aerospace Science and Technology, Volume 68
      Author(s): Xiao Tang, Jiaqi Luo, Feng Liu
      An adjoint-response surface method is developed to provide efficient surrogate model in a parametrized design space for aerodynamic optimization of turbomachinery blades. Our goal is to improve the adiabatic efficiency or equivalently reduce the entropy generation through blade row with a mass flow rate constraint. Firstly, an aerodynamic sensitivity analysis is conducted with a viscous adjoint method to find the suitable number of control points on the suction surface of the transonic NASA rotor 67. Then quadratic polynomial (QP) based response surfaces of 4, 6 and 8 parameters are examined to validate the advantages of the gradient-enhanced model. In the following 24-parameter aerodynamic design optimization case, a steepest descent optimization (SDO) based on adjoint gradient is conducted, then QP based response surface model is constructed using both the values of cost function and its adjoint gradients with respect to geometry control parameters. We present the geometric features, overall aerodynamic improvements and flow details of optimal designs given by SDO and gradient-enhanced response surface model (GERSM). The effects of blade reshaping on shock system, tip clearance flow and flow separation at hub are examined. Also, off-design performances are analyzed regarding both adiabatic efficiency and stall margin.

      PubDate: 2017-05-20T16:24:05Z
      DOI: 10.1016/j.ast.2017.05.005
      Issue No: Vol. 68 (2017)
       
  • Research on centrifugal compressor disk containment of auxiliary power
           unit
    • Authors: Conger Bai; Haijun Xuan; Zekan He; Yushen Zou; Guang Tang; Jin Tang
      Pages: 37 - 45
      Abstract: Publication date: September 2017
      Source:Aerospace Science and Technology, Volume 68
      Author(s): Conger Bai, Haijun Xuan, Zekan He, Yushen Zou, Guang Tang, Jin Tang
      To investigate the centrifugal compressor disk containment of auxiliary power unit (APU) in gas turbine, research on specific compressor is conducted in combination of simulations and tests. Nonlinear explicit finite element analysis of tri-hub fragments impacting containment assembly is carried out using LS-DYNA. Impacting characteristics in each period are discussed. Strength of the outer cover, the back shroud and the connecting bolts between them is further studied through simulation. The results show that the fragments interact with the outer cover and the back shroud both in rotating plane and axial direction. The internal energy is mostly composed of the strain energy of the impeller. Insufficient strength of each component leads to an uncontained result. Potential failure modes are discussed. Verification tests on high-speed spin tester revealing both contained and uncontained cases have been conducted and showed that the outer cover, the back shroud and the connecting bolts between them all play a significant role to containment. Adequate strength of these components is essential. Otherwise the outer cover will detach away and the back shroud will be damaged.

      PubDate: 2017-05-20T16:24:05Z
      DOI: 10.1016/j.ast.2017.05.002
      Issue No: Vol. 68 (2017)
       
  • Robust finite time control algorithm for satellite attitude control
    • Authors: You Li; Dong Ye; Zhaowei Sun
      Pages: 46 - 57
      Abstract: Publication date: September 2017
      Source:Aerospace Science and Technology, Volume 68
      Author(s): You Li, Dong Ye, Zhaowei Sun
      Finite time controllers robust to inertia matrix uncertainty for satellite attitude stabilization control and attitude tracking control are developed in this paper. A three-stage finite sliding mode is constructed to improve system convergence rate. The singularity issue is solved by using the property of Euler Axis when it's paralleled to angular velocity. Based on this finite time sliding mode, finite time controller is developed to ensure the system state could reach the sliding mode in finite time. System inertia matrix uncertainty and disturbance torque is considered in this paper. The control torque constraint is also considered to ensure the norm of control torque does not exceed system upper bound. Finite time stability of the controller is proved and the controller performance is demonstrated by simulation results.

      PubDate: 2017-05-20T16:24:05Z
      DOI: 10.1016/j.ast.2017.05.014
      Issue No: Vol. 68 (2017)
       
  • 3D grain burnback analysis using the partial interface tracking method
    • Authors: Wando Ki; Taeho Ko; Sangmin Kim; Woongsup Yoon
      Pages: 58 - 67
      Abstract: Publication date: September 2017
      Source:Aerospace Science and Technology, Volume 68
      Author(s): Wando Ki, Taeho Ko, Sangmin Kim, Woongsup Yoon
      The evolution of multi-dimensional grains of solid rocket motor propellant was carried out using the partial interface tracking method. This method applies the Lagrangian approach to the axisymmetric area of the X–Y plane and the fin area of the Y–Z plane to analyze the multi-dimensional grain burnback. The Lagrangian approach is an effective way to simulate the axisymmetric or 2D shape of a grain, but it is difficult to determine the 3D shape using this method. Therefore, the partial interface tracking method was designed to solve this problem and to get solutions quickly. The grid data resulting from this method is generated in a standard file format, which makes it easy to check the grid shape through commercial modeling software. This method showed good agreement with previous literature and was effective for numerous different grains. Also, it was confirmed that the code can be applicable to the 0D flow field model.

      PubDate: 2017-05-26T02:02:20Z
      DOI: 10.1016/j.ast.2017.04.023
      Issue No: Vol. 68 (2017)
       
  • Design and structural analysis of unique structures under an internal
           vacuum
    • Authors: Brian Cranston; Mohammed AlGhofaily; Anthony Palazotto
      Pages: 68 - 76
      Abstract: Publication date: September 2017
      Source:Aerospace Science and Technology, Volume 68
      Author(s): Brian Cranston, Mohammed AlGhofaily, Anthony Palazotto
      This paper details an experiment that was used to validate the frame deformation of three vacuums lighter than air vehicle finite element models composed of a frame with a skin covering. The experiment consisted of a simplified one directional loading to determine the behavior of a 3D printed frame, which was compared to a corresponding finite element model. A 3D printed icosahedron frame was loaded in compression using a mechanical testing machine to record the load versus displacement of the structure. It was discovered that the material properties of the printed structure were significantly lower than the quoted values from the manufacturer. The modulus property was extracted from the finite element model that best matched the experiment. The behavior of the frame from the experiment shows that the beams do buckle. The model matches the frame buckling and load retention. The feasibility of a vacuum lighter than air vehicle using an icosahedron, hexakis icosahedron, and celestial frame and skin were then analyzed since the method of analysis was proven through the experiment. The icosahedron showed failure due to material limits and the hexakis icosahedron showed definite feasibility using modern material properties.

      PubDate: 2017-05-26T02:02:20Z
      DOI: 10.1016/j.ast.2017.04.028
      Issue No: Vol. 68 (2017)
       
  • Mixing augmentation induced by a vortex generator located upstream of the
           transverse gaseous jet in supersonic flows
    • Authors: Lang-quan Li; Wei Huang; Li Yan
      Pages: 77 - 89
      Abstract: Publication date: September 2017
      Source:Aerospace Science and Technology, Volume 68
      Author(s): Lang-quan Li, Wei Huang, Li Yan
      The mixing process plays a very important role in the engineering realization of the scramjet engine, and sufficient mixing between the incoming supersonic air and the fuel relates to improve the overall performance of the airbreathing hypersonic propulsion system. In the current study, the delta wing is placed in front of the injector to promote the mixing of fuel and supersonic crossflow, and the effects of the delta wing height and the jet-to-crossflow pressure ratio have been investigated numerically based on grid independency analysis and code validation. The obtained results predicted by the three-dimensional Reynolds-average Navier–Stokes (RANS) equations coupled with the two equation k – ω shear stress transport (SST) turbulence model show that the delta wing has a highly remarkable improvement on mixing characteristics such as mixing efficiency and fuel penetration depth. However, the delta wing also shows additional losses of stagnation pressure. In the case of higher values of delta wing height and jet-to-crossflow pressure ratio, higher penetration and more losses of stagnation pressure are shown. At the same time, the mixing efficiency decreases with the increase of the jet-to-crossflow pressure ratio irrespective of the height of the delta wing, and there is an optimum height of the delta wing for each jet-to-crossflow pressure ratio to achieve the maximization of rapid fuel–air mixing. In addition, the hydrogen content in the recirculation region between the orifice and the delta wing is a result of both the jet-to-crossflow pressure ratio and the height of the delta wing. In conclusion, the design of the flow field with the delta wing to realize objective comprehensive optimal performance is a multi-objective problem, and it should be solved by the multi-objective design optimization approach.

      PubDate: 2017-05-26T02:02:20Z
      DOI: 10.1016/j.ast.2017.05.016
      Issue No: Vol. 68 (2017)
       
  • Regression rate characteristics of hybrid rocket motor with helical grain
    • Authors: Hui Tian; Yuelong Li; Chengen Li; Xingliang Sun
      Pages: 90 - 103
      Abstract: Publication date: September 2017
      Source:Aerospace Science and Technology, Volume 68
      Author(s): Hui Tian, Yuelong Li, Chengen Li, Xingliang Sun
      This paper concentrates on the fuel regression rate characteristics of hybrid rocket motor with helical grain and attempts to overcome the low regression rate shortcoming of conventional hybrid rocket motor. Both three-dimensional numerical simulations and lab-scale firing tests are conducted to analyze the regression behavior of solid helical fuel grain. Gaseous oxygen and polyethylene are utilized as the propellants. Head axial injection method and Laval nozzle are adopted in the motor. A steady numerical model based on pure-gas-phase reaction assumption is established. Flow field characteristics of the hybrid rocket motor with helical grain are identified through three-dimensional numerical simulations. Simulation results show that the helical structure can both increase turbulence kinetic energy and swirl number in the flow field. These two factors both contribute to the increase of the fuel regression rate. Geometric factors influencing the fuel regression rate are thread pitch, groove depth and groove width. Experimental results reveal that the fuel regression rate increases with the increase of the groove depth and the groove width. The thread pitch can also obviously influence the regression behavior of the helical grain. Overall, the helical grain can effectively increase the fuel regression rate of hybrid rocket motor.

      PubDate: 2017-05-26T02:02:20Z
      DOI: 10.1016/j.ast.2017.05.006
      Issue No: Vol. 68 (2017)
       
  • A new Multi-position calibration method for gyroscope's drift coefficients
           on centrifuge
    • Authors: Shi-ming Wang; Ni Meng
      Pages: 104 - 108
      Abstract: Publication date: September 2017
      Source:Aerospace Science and Technology, Volume 68
      Author(s): Shi-ming Wang, Ni Meng
      In order to accurately calibrate the gyroscope's drift coefficients, the coordinate systems are established on precision centrifuge with counter-rotating platform, and the corresponding error sources of each coordinate system are analyzed. The precise input angular rate along each axis of gyroscope are derived by homogeneous transformation method and also the nominal input specific forces are given. The precise expression of each drift coefficient is provided combining with gyroscope's error model, input specific forces and angular rates of gyroscope at the 16-position. And the compensation for the identification results can be conducted by the expression. It can be shown that through simulation two coefficients are significantly influenced by centrifuge errors when using the 16-position calibration method, and centrifuge errors have no impacts on other coefficients, which proves that the method can effectively eliminate the impacts of centrifuge errors. Only several centrifuge errors should be considered in actual calibration such as the perpendicularity between the counter rotating platform's revolving axis and the working base, the wobbles of counter rotating platform, and the difference between the angular rate of counter rotating platform and the one of the main axis.

      PubDate: 2017-05-26T02:02:20Z
      DOI: 10.1016/j.ast.2017.05.001
      Issue No: Vol. 68 (2017)
       
  • Aircraft navigation based on differentiation–integration observer
    • Authors: Xinhua Wang; Lilong Cai
      Pages: 109 - 122
      Abstract: Publication date: September 2017
      Source:Aerospace Science and Technology, Volume 68
      Author(s): Xinhua Wang, Lilong Cai
      In this paper, a generalized differentiation–integration observer is presented based on sensors selection. The proposed differentiation–integration observer can estimate the multiple integrals and high-order derivatives of a signal, synchronously. The parameters selection rules are presented for the differentiation–integration observer. The theoretical results are confirmed by the frequency–domain analysis. The effectiveness of the proposed observer is verified through the numerical simulations on a quadrotor aircraft: i) through the differentiation–integration observer, the attitude angle and the uncertainties in attitude dynamics are estimated synchronously from the measurements of angular velocity; ii) a control law is designed based on the observers to drive the aircraft to track a reference trajectory.

      PubDate: 2017-05-26T02:02:20Z
      DOI: 10.1016/j.ast.2017.05.007
      Issue No: Vol. 68 (2017)
       
  • Constitutive modeling of solid propellants for three dimensional nonlinear
           finite element analysis
    • Authors: Birkan
      Abstract: Publication date: October 2017
      Source:Aerospace Science and Technology, Volume 69
      Author(s): Birkan Tunç, Şebnem Özüpek
      A three dimensional constitutive model for solid propellants is proposed and implemented in a finite element software. The effects of viscoelasticity, large deformation, temperature, pressure, softening in monotonic and cyclic loadings are represented. Damage is assumed to initiate by failure of the particle-binder bond or failure in the binder itself. Opening of the micro-cracks resulting from either failure is associated with the evolution of damage. Stress softening during unloading and reloading is captured via a cyclic function modifying the viscoelastic stress. The implementation algorithm is stable and robust, therefore analysis of general geometries and loadings are possible. The model may be calibrated with a small number of test data, therefore is suitable for practical use in the industry.

      PubDate: 2017-07-20T17:32:53Z
       
 
 
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