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  Subjects -> AERONAUTICS AND SPACE FLIGHT (Total: 101 journals)
Showing 1 - 30 of 30 Journals sorted alphabetically
Acta Astronautica     Hybrid Journal   (Followers: 276)
Advances in Space Research     Full-text available via subscription   (Followers: 313)
Aeronautica     Open Access   (Followers: 20)
Aerospace     Open Access   (Followers: 38)
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 186)
Aerospace Science and Technology     Hybrid Journal   (Followers: 288)
AIAA Journal     Full-text available via subscription   (Followers: 709)
Air Force Magazine     Full-text available via subscription   (Followers: 8)
Air Medical Journal     Hybrid Journal   (Followers: 3)
Aircraft Engineering and Aerospace Technology     Hybrid Journal   (Followers: 144)
American Journal of Space Science     Open Access   (Followers: 105)
Annual of Navigation     Open Access   (Followers: 20)
Artificial Satellites : The Journal of Space Research Centre of Polish Academy of Sciences     Open Access   (Followers: 17)
ASTRA Proceedings     Open Access   (Followers: 1)
Aviation     Hybrid Journal   (Followers: 10)
Aviation Psychology and Applied Human Factors     Hybrid Journal   (Followers: 14)
Aviation Week     Full-text available via subscription   (Followers: 213)
Aviation, Space, and Environmental Medicine     Full-text available via subscription   (Followers: 8)
Canadian Aeronautics and Space Journal     Full-text available via subscription   (Followers: 26)
CEAS Aeronautical Journal     Hybrid Journal   (Followers: 27)
Chinese Journal of Aeronautics     Open Access   (Followers: 15)
Ciencia y Poder Aéreo     Open Access   (Followers: 1)
Control Systems     Hybrid Journal   (Followers: 88)
Cosmic Research     Hybrid Journal   (Followers: 3)
COSPAR Colloquia Series     Full-text available via subscription   (Followers: 6)
Egyptian Journal of Remote Sensing and Space Science     Open Access   (Followers: 20)
Elsevier Astrodynamics Series     Full-text available via subscription   (Followers: 3)
Fatigue of Aircraft Structures     Open Access   (Followers: 11)
Frontiers in Aerospace Engineering     Open Access   (Followers: 11)
Frontiers in Astronomy and Space Sciences     Open Access   (Followers: 9)
Giroskopiya i Navigatsiya     Open Access  
Gyroscopy and Navigation     Hybrid Journal   (Followers: 185)
IEEE Aerospace and Electronic Systems Magazine     Full-text available via subscription   (Followers: 123)
IEEE Transactions on Circuits and Systems I: Regular Papers     Hybrid Journal   (Followers: 23)
International Journal of Aeroacoustics     Hybrid Journal   (Followers: 29)
International Journal of Aerodynamics     Hybrid Journal   (Followers: 18)
International Journal of Aerospace Engineering     Open Access   (Followers: 64)
International Journal of Aerospace Innovations     Full-text available via subscription   (Followers: 17)
International Journal of Aerospace Sciences     Open Access   (Followers: 21)
International Journal of Applied Geospatial Research     Hybrid Journal   (Followers: 3)
International Journal of Aviation Management     Hybrid Journal   (Followers: 6)
International Journal of Aviation Psychology     Hybrid Journal   (Followers: 12)
International Journal of Aviation Technology, Engineering and Management     Full-text available via subscription   (Followers: 4)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 8)
International Journal of Flow Control     Full-text available via subscription   (Followers: 5)
International Journal of Hypersonics     Full-text available via subscription   (Followers: 4)
International Journal of Micro Air Vehicles     Full-text available via subscription   (Followers: 8)
International Journal of Satellite Communications Policy and Management     Hybrid Journal   (Followers: 6)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 5)
International Journal of Space Structures     Full-text available via subscription   (Followers: 7)
International Journal of Space Technology Management and Innovation     Full-text available via subscription   (Followers: 5)
International Journal of Sustainable Aviation     Hybrid Journal   (Followers: 2)
International Journal of Turbo & Jet-Engines     Hybrid Journal   (Followers: 3)
Journal of Aeronautical Materials     Open Access   (Followers: 2)
Journal of Aeronautics & Aerospace Engineering     Open Access   (Followers: 10)
Journal of Aerospace Engineering     Full-text available via subscription   (Followers: 54)
Journal of Aerospace Engineering & Technology     Full-text available via subscription   (Followers: 8)
Journal of Aerospace Information Systems     Full-text available via subscription   (Followers: 4)
Journal of Aerospace Technology and Management     Open Access   (Followers: 3)
Journal of Aircraft     Full-text available via subscription   (Followers: 181)
Journal of Airline and Airport Management     Open Access   (Followers: 8)
Journal of Astrobiology & Outreach     Open Access   (Followers: 2)
Journal of Aviation Technology and Engineering     Open Access   (Followers: 10)
Journal of Guidance, Control, and Dynamics     Full-text available via subscription   (Followers: 115)
Journal of Konbin : The Journal of Air Force Institute of Technology     Open Access   (Followers: 1)
Journal of Navigation     Hybrid Journal   (Followers: 177)
Journal of Propulsion and Power     Full-text available via subscription   (Followers: 344)
Journal of Space Weather and Space Climate     Open Access   (Followers: 20)
Journal of Spacecraft and Rockets     Full-text available via subscription   (Followers: 495)
Journal of Spatial Science     Hybrid Journal   (Followers: 3)
Journal of the American Helicopter Society     Full-text available via subscription   (Followers: 4)
Journal of the Astronautical Sciences     Hybrid Journal   (Followers: 4)
Journal of Wind Engineering and Industrial Aerodynamics     Hybrid Journal   (Followers: 6)
Life Sciences in Space Research     Hybrid Journal   (Followers: 1)
MAD - Magazine of Aviation Development     Open Access   (Followers: 1)
Microgravity Science and Technology     Hybrid Journal   (Followers: 1)
New Space     Hybrid Journal   (Followers: 3)
Nonlinear Dynamics     Hybrid Journal   (Followers: 7)
npj Microgravity     Open Access   (Followers: 1)
Population Space and Place     Hybrid Journal   (Followers: 4)
Problemy Mechatroniki. Uzbrojenie, lotnictwo, inżynieria bezpieczeństwa / Problems of Mechatronics. Armament, Aviation, Safety Engineering     Open Access  
Proceedings of the Human Factors and Ergonomics Society Annual Meeting     Hybrid Journal   (Followers: 8)
Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering     Hybrid Journal   (Followers: 41)
Progress in Aerospace Sciences     Full-text available via subscription   (Followers: 69)
Propulsion and Power Research     Open Access   (Followers: 24)
REACH - Reviews in Human Space Exploration     Full-text available via subscription   (Followers: 1)
Recent Patents on Space Technology     Full-text available via subscription   (Followers: 1)
Research & Reviews : Journal of Space Science & Technology     Full-text available via subscription   (Followers: 7)
RocketSTEM     Free   (Followers: 2)
Russian Aeronautics (Iz VUZ)     Hybrid Journal   (Followers: 24)
Space and Polity     Hybrid Journal   (Followers: 4)
Space Policy     Hybrid Journal   (Followers: 25)
Space Research Today     Full-text available via subscription   (Followers: 41)
Space Safety Magazine     Free   (Followers: 41)
Space Science Reviews     Hybrid Journal   (Followers: 90)
SpaceNews     Free   (Followers: 506)
Transport and Aerospace Engineering     Open Access   (Followers: 6)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 5)
Unmanned Systems     Hybrid Journal   (Followers: 2)
Вісник Національного Авіаційного Університету     Open Access   (Followers: 1)
Вестник УГАТУ     Open Access  

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Journal Cover CEAS Aeronautical Journal
  [SJR: 0.499]   [H-I: 6]   [27 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1869-5582
   Published by Springer-Verlag Homepage  [2335 journals]
  • Numerical simulations of streamwise vortices on a high-lift wing
    • Authors: T. Landa; R. Radespiel; J. Wild
      Pages: 3 - 15
      Abstract: Abstract This contribution presents results of numerical simulations on a generic high-lift configuration. Properties of the computational grid are briefly described. The numerical simulations are performed with the DLR-TAU-Code at different angles of attack up to stall. The Menter-SST eddy viscosity turbulence model and the JHh-v2 Reynolds stress model are applied. Streamwise vortices arise at the edge of a slat, which is cut off in the spanwise direction, and the corresponding edge of the clean nose. These vortices interact with the flow along the suction side of the wing. While proceeding downstream, a strong interaction between the vortices is observed for high angles of attack. The behavior of the vortex system and the influence on the high-lift performance of the configuration is characterized. In particular, the effect of the applied turbulence models of different types on the prediction of the vortex behavior is shown within this contribution.
      PubDate: 2017-03-01
      DOI: 10.1007/s13272-016-0217-0
      Issue No: Vol. 8, No. 1 (2017)
       
  • Experimental aerodynamic assessment and evaluation of an agile highly
           swept aircraft configuration
    • Authors: Kerstin C. Huber; Andreas Schütte; Martin Rein; Thomas Löser
      Pages: 17 - 29
      Abstract: Abstract Extensive experimental and numerical investigations on a highly swept generic unmanned combat aerial vehicle (UCAV) configuration of lambda type with a variable leading edge contour have been conducted. Within these investigations, it was shown that the flow field is dominated by complex vortex systems including vortex-to-vortex and vortex-to-boundary layer interactions. The vortex-dominated flow field has a strong nonlinear influence on the aerodynamic behavior of the configuration. Hence, controllability is demanding and poses a real challenge in the design of these kinds of configurations. Especially, the dimensioning of the control surfaces, for the lateral- and longitudinal stability of tailless configurations of low aspect ratio and high leading-edge sweep, poses a challenging task which is not yet solved. To understand the problem of lacking lateral- and longitudinal stability for these kinds of configurations, experiments in the subsonic and transonic flow regime have been conducted for the Stability and Control Configuration (SACCON), which has a leading edge sweep of 53°, to assess the control surface effectiveness of conventional trailing-edge control devices. The present study reviews the experimental investigations conducted with the highly swept generic UCAV configuration SACCON.
      PubDate: 2017-03-01
      DOI: 10.1007/s13272-016-0219-y
      Issue No: Vol. 8, No. 1 (2017)
       
  • Influences of voltage variations on electric power architectures for
           hybrid electric aircraft
    • Authors: Patrick C. Vratny; Holger Kuhn; Mirko Hornung
      Pages: 31 - 43
      Abstract: Abstract Hybrid electric and universally electric aircraft seem to be one possible option to fulfil ambitious future emission and noise reduction targets forced by the European Commission with the Strategic Research and Innovation Agenda and the NASA with the NASA N+3 goals. The overall vehicular efficiency of such concepts can be considerably improved. A key element is the design of the electric power train system with regard to efficiency and also mass. Based on a battery-powered direct current (DC) system architecture, the efficiency impact of different design voltages has been investigated in this paper. The main components within a DC electric architecture are power electronics such as converters and inverters, transmission cables, protection devices and cooling systems. Especially, the power electronics show the highest sensitivity when choosing a design system voltage. Two main losses occur within those components, conduction losses and switching losses. While conduction losses decrease with an increase in the design voltage, switching losses normally increase. Therefore, for a required design power there will be a trade-off between conduction and switching losses. For that purpose, two different architecture design philosophies were investigated to compare the system efficiencies at different design voltages. The first architecture is the constant system voltage (CSV) architecture, which compensates a decreasing output voltage of a battery, and a variable system voltage (VSV) architecture, which does not compensate this voltage drop. It has been identified that for an electric power train system delivering a constant power of 6000 kW, the VSV shows the best efficiency. The optimum system voltage of the VSV architecture is near the operating voltage of the electric motor, while the optimum system voltage of the CSV architecture was identified at higher voltages. These results will serve as baseline for the identification of the best voltage level for a mass- and efficiency-optimized system.
      PubDate: 2017-03-01
      DOI: 10.1007/s13272-016-0218-z
      Issue No: Vol. 8, No. 1 (2017)
       
  • Adaptive internal model control research in autonomous landing phase for a
           fixed-wing UAV
    • Authors: Jiu-zhou Gao; Hong-guang Jia
      Pages: 45 - 51
      Abstract: Abstract Autonomous landing is a very complex phase of flight for unmanned aerial vehicle (UAV). Adaptive internal model control (AIMC) is proposed and applied on autonomous landing control system in this paper. Controllers are designed based on the decoupled and linearized models of a sample UAV. Estimation of process model is carried out to enhance system robustness, and filter parameter adjustment is proposed to achieve a good dynamic performance. Control effects are compared and analyzed between IMC and AIMC in different wind conditions which demonstrate that AIMC has better performances than IMC. At last, Monte Carlo simulations prove the system stability.
      PubDate: 2017-03-01
      DOI: 10.1007/s13272-016-0216-1
      Issue No: Vol. 8, No. 1 (2017)
       
  • Sizing of the energy storage system of hybrid-electric aircraft in general
           aviation
    • Authors: I. Geiß; R. Voit-Nitschmann
      Pages: 53 - 65
      Abstract: Abstract The advantages of electric drives and conventional combustion engines can be combined in series hybrid-electric aircraft through appropriate aircraft design. As a consequence, energy-efficient aircraft with sufficient range can be realised in general aviation. The sizing of the energy storage system has a significant impact on the range, the energy consumption, and the related energy cost of the aircraft. In this paper, the boundary conditions for the sizing of the energy storage are analysed. Based upon this, a design for an energy-optimized aircraft will be suggested. The energy consumption of this aircraft will then be compared to modern conventional aircraft.
      PubDate: 2017-03-01
      DOI: 10.1007/s13272-016-0220-5
      Issue No: Vol. 8, No. 1 (2017)
       
  • Design and sizing of a parametric structural model for a UCAV
           configuration for loads and aeroelastic analysis
    • Authors: Arne Voss; Thomas Klimmek
      Pages: 67 - 77
      Abstract: Abstract The authors present the setup of a parametric structural finite element model for the loads and aeroelastic analysis of an unmanned combat air vehicle (UCAV). The DLR-F19 is a “flying wing” configuration with a geometry based on previous research conducted in the scope of the “Mephisto” project and its predecessors “FaUSST” and “UCAV2010”. While a considerable body of knowledge exists regarding conventional configurations, unconventional configurations lack that same level of experience, and data for comparison is rarely available. Using an adequate structural model, the conceptual design stage becomes more sophisticated and already allows for the investigation of physical effects at an early stage of the design process. Strategies for structural modeling and proper condensation, aero-structural coupling, loads integration, control surface attachment, and the use of composite materials are addressed in this paper. The resulting model is sized for minimum structural weight, taking into account 216 load cases. In addition, a comprehensive loads analysis campaign is conducted and the resulting loads are evaluated at defined monitoring stations. In addition to maneuver loads, quasi-static gust loads are calculated using the Pratt formula and compared to results obtained from a dynamic 1-cosine gust simulation. The reasons for higher loads of the Pratt formula based method are discussed. The conclusion is that the Pratt formula is suitable for the preliminary sizing of “flying wing” configurations.
      PubDate: 2017-03-01
      DOI: 10.1007/s13272-016-0223-2
      Issue No: Vol. 8, No. 1 (2017)
       
  • A two-element high-lift airfoil in disturbed flow conditions
    • Authors: S. Klein; P. Scholz; R. Radespiel
      Pages: 79 - 91
      Abstract: Abstract This contribution presents experimental results of a two-element high-lift airfoil in a disturbed inflow. Permanent disturbances are generated by the wakes of two static airfoils located upstream of the research airfoil, one of which is a planar wake by an infinite airfoil and the other is a longitudinal vortex emanating from a finite wing. The disturbances induce spanwise gradients into the flow. The disturbed flow field is measured by Particle Image Velocimetry. The interaction of the disturbed flow field with the high-lift airfoil is investigated by means of static surface pressure close to the airfoil’s leading- and trailing-edge, as well as surface hotfilm measurements and oil flow visualizations on the high-lift flap. For small and moderate incidences the airfoil is mainly influenced by the circulation induced by the disturbances, which affect the effective flow angles. Local effects that result from the turbulence in the airfoil-wake and the induced transverse velocity of the disturbances are likewise considered. At high angle of attack, the prevailing stall conditions with strong variations in spanwise direction are discussed.
      PubDate: 2017-03-01
      DOI: 10.1007/s13272-016-0221-4
      Issue No: Vol. 8, No. 1 (2017)
       
  • An estimation of the UV radiation inside the cockpits of large commercial
           jets
    • Authors: Ralf Meerkötter
      Pages: 93 - 104
      Abstract: Abstract UV irradiances and UV doses inside the cockpit of large commercial jets are estimated. Results are based on radiative transfer calculations taking into account the spectral transmittances and the limited fields of view of large commercial jet windscreens. In a first step, vertical profiles of UV irradiances for a cloud free atmosphere over snow free and snow covered surfaces and for an atmosphere containing a water cloud layer are simulated. It turns out that the windscreens block the UV-B radiation and transmit parts of the UV-A radiation. Comparing UV irradiances inside and outside the cockpit show that the intensity of UV radiation inside strongly depends on whether the direct sun is entering the cabin or not. Without direct sun the diffuse UV radiation inside the cockpit amounts to about 5% the ambient UV irradiance outside the aircraft. In cases of low sun when direct radiation can reach the pilot, percentages grow from 50 to 100% with increasing solar zenith angle. A water cloud layer between 2 and 4 km increases the UV irradiances inside a cockpit by about 7% at 10 km altitude when compared to the cloud free atmosphere. A snow covered surface causes a similar increase. Finally, and by the aid of MOZAIC waypoint data UV doses were estimated for selected long-distance flights between Europe and the overseas continents North and South America, South Africa, and East Asia. UV doses are affected by takeoff and landing time, by the sun position relative to the aircraft heading during flight, and by the day of the year. UV doses inside the cockpit amount to maximum 60% the UV doses outside at the same altitude, however, in most cases percentages are between about 10 and 40%.
      PubDate: 2017-03-01
      DOI: 10.1007/s13272-016-0225-0
      Issue No: Vol. 8, No. 1 (2017)
       
  • Experimental investigation and design of a shape-variable compressor
           cascade
    • Authors: J. H. Krone; O. Huxdorf; J. Riemenschneider; H. P. Monner; F. Schur; J. Friedrichs; M. Wiedemann
      Pages: 105 - 127
      Abstract: Abstract The design of jet engine compressor blading always implies a compromise between design and off-design operation. The reason for this is a fixed blade geometry which has to be operated over a wide range of operating conditions. Consequently, maximum achievable efficiencies at design operation are limited by off-design requirements, e.g., a certain stall margin. This paper describes an approach using shape-variable blades equipped with integrated piezoceramic-based macro fiber composite (MFC) Actuators on the blade’s suction and pressure sides. By applying a voltage to these actuators, it is possible to increase and to decrease the blade stagger angle and therefore the blade turning. Compared to a conventional fixed blade profile, the actuated design is thus adaptable within a certain range regarding ambient conditions. The first part of the paper describes the geometry and structure of the shape-variable blades for use in a compressor cascade experiment. In the next part, the three-dimensional deformation behavior of all manufactured blades at different shape conditions is characterized with a photogrammetric measurement system called ATOS. The first results without aerodynamic loads show an average displacement at the trailing edge of approximately Δz ≈ 0.9 mm compared to the non-actuated condition. This corresponds to an average outlet angle variation of approximately ∆κ2 ≈ ± 1°. The third part of the paper presents the results of the low speed cascade experiment using a fully actuated cascade. On the one hand, the objective is to determine the influence of blade actuation on aerodynamic characteristics such as flow outlet angle, total pressure loss and pressure distributions. On the other hand, optical blade displacement measurements are used to investigate combined 2D- and 3D-deformation effects of blade actuation in conjunction with aerodynamic loads. For these measurements, the ATOS system is also used. The wake evaluations show that maximum blade actuation leads to flow outlet angle deviations up to ± 1° which can be described by an almost linear shift of the cascade performance without changing the loss distribution significantly. Furthermore, for the chosen profile this margin is approximately constant over the operating range.
      PubDate: 2017-03-01
      DOI: 10.1007/s13272-016-0224-1
      Issue No: Vol. 8, No. 1 (2017)
       
  • Multi-scale analysis and optimisation of three-dimensional woven composite
           structures combining response surface method and genetic algorithms
    • Authors: Xinwei Fu; Sergio Ricci; Chiara Bisagni
      Pages: 129 - 141
      Abstract: Abstract The paper proposes an optimisation strategy for the design of structures made of three-dimensional woven composites. The knowledge of the weaving architecture is essential to properly optimise the design of the structural components subjected to specific load conditions. Owing to the hierarchy and periodicity of the textile composite materials, a multi-scale parameterisation modelling strategy combining the adoption of a representative volume element and periodic boundary conditions is employed to estimate the behaviour of stiffened panels. In order to minimise the expensive computational cost, response surface method techniques are used to generate the approximated structural responses in an efficient and applicable way. The approach here proposed consists of a multi-scale parameterization analysis strategy and an optimisation framework based on the response surface technique and genetic algorithms. The optimal design results are verified by finite element analysis proving that the response surface method integrated with genetic algorithms allows to easily investigate the influence of the fabrics constitutive parameters on the structural behaviour.
      PubDate: 2017-03-01
      DOI: 10.1007/s13272-016-0227-y
      Issue No: Vol. 8, No. 1 (2017)
       
  • Thanks to our Reviewers
    • PubDate: 2017-01-31
      DOI: 10.1007/s13272-017-0236-5
       
  • State estimation for reactive Euler equation by Kalman Filtering
    • Authors: Jan- Simon Schäpel; Sascha Wolff; Philipp Schulze; Phillip Berndt; Rupert Klein; Volker Mehrmann; Rudibert King
      Abstract: Abstract In this article, we present a state estimation method for an approximately constant volume combustion process. This is an Unscented Kalman Filter used to estimate quantities which are of interest for the combustion process inside the considered combustion tube, i.e., the pressure, velocity and temperature field. This algorithm relies only on a small number of discrete pressure measurements along the combustion tube. The proposed methods are applied in numerical simulations to demonstrate their effectiveness. In a one-dimensional simulator, the flow field in the tube is described by the one-dimensional Euler equations with chemical source terms. To keep the computational effort on a manageable level, the Kalman Filter is built based on a reduced model. Thus, the model reduction for the Euler equations in combination with chemical kinetics is another focus of this contribution.
      PubDate: 2017-01-18
      DOI: 10.1007/s13272-016-0229-9
       
  • Numerical investigation of the vortex roll-up from a helicopter blade tip
           using a novel fixed-wing adaptation method
    • Authors: Antoine Joulain; Damien Desvigne; David Alfano; Thomas Leweke
      Abstract: Abstract This contribution relates to the simulation of the flow around the tip of a helicopter rotor blade in hovering flight conditions. We here propose a new methodology of framework adaptation, using a comprehensive rotor code and high-fidelity numerical simulations. We construct an equivalent fixed-wing configuration from a rotating blade, in which centrifugal and Coriolis forces are neglected. The effect of this approximation on the solution is analyzed. The method is validated by a detailed comparison with wind tunnel data from the literature, concerning aerodynamic properties and tip vortex roll-up. This validation also includes variations of the pitch angle and rotational speed, up to transonic tip velocities. Compared to previously published methods of framework adaptation, the new hybrid method is found to reproduce more accurately the flow around a rotating-blade tip.
      PubDate: 2017-01-07
      DOI: 10.1007/s13272-016-0234-z
       
  • Time-domain output error system identification of iced aircraft
           aerodynamics
    • Authors: Christoph Deiler
      Abstract: Abstract A \(\Delta\) -model approach to characterize changed aircraft dynamics due to icing is analytically derived and its parameters are estimated. The model extension is formulated as a separate module in the aircraft flight mechanics simulation and can be used in existing simulation models. The application of the output error method in time domain allows to satisfactorily match model outputs and measurements as well as calculated aerodynamic derivatives. Using available flight data of a light business jet with different ice accumulation cases provided by EMBRAER, model parameters of the \(\Delta\) -model are determined and interpreted pertaining to the aerodynamic degradation caused by icing. The results show good promise that the combination of modeling approach and estimation technique could be applicable to extend existing simulator models providing a basis for pilot training under icing conditions.
      PubDate: 2017-01-04
      DOI: 10.1007/s13272-016-0231-2
       
  • Closed-loop active flow control of a non-steady flow field in a
           highly-loaded compressor cascade
    • Authors: M. Staats; W. Nitsche; S. J. Steinberg; R. King
      Abstract: Abstract The provision of secure compressor operation under circumstances of a pulsed detonation engine is crucial for the success of pressure gaining combustion processes for turbo machinery applications. This paper discusses active flow control as a possible solution to approach this challenge. The presented experiments were conducted on a highly loaded low speed linear compressor stator cascade operated at \(Re=600{,}000\) and \(Ma =0.07\) . A choking-device which was located in the wake of the cascade simulated the non-steady outflow condition that is expected under the conditions of pressure gaining combustion. In the discussed experiments, the choking-device generated a periodic disturbance to every passage at a typical Strouhal number of \(Sr =0.03\) . The flow structures of the non-steady flow field were strongly correlated to the working-phase of the choking-device. In this paper, an iterative learning controller was used to find an optimized actuation trajectory that was used for closed-loop sidewall-actuation to control the corner separation in the non-steady flow field. The iterative learning controller took advantage of the periodicity of the disturbance to calculate a non-steady actuation trajectory that optimally suppressed the impact of the choking-device on the flow. The active flow control effect was evaluated by means of static pressure rise using five hole probe measurements in the wake of one passage.
      PubDate: 2016-12-22
      DOI: 10.1007/s13272-016-0232-1
       
  • Identification of rotor wake inflow finite-state models for flight
           dynamics simulations
    • Authors: Massimo Gennaretti; Riccardo Gori; Jacopo Serafini; Felice Cardito; Giovanni Bernardini
      Abstract: Abstract The aim of this work is the development of dynamic, finite-state modelling of wake inflow generated by kinematic perturbations of rotors in steady flight conditions. Extracted from responses of high-fidelity aerodynamic solvers, it is suited for flight dynamics applications. A three-step identification procedure is proposed: (1) evaluation by a high-fidelity solver of the wake inflow due to harmonic perturbations of rotor kinematics, (2) determination of the corresponding inflow coefficient transfer functions, and (3) rational approximation of the transfer functions. Wake inflow models related to rotor loads (like the well-known Pitt–Peters model) are obtained, as well, as by-products of that proposed. Considering aerodynamic simulations provided by a solver based on a boundary element method for potential flows, the numerical investigation presents the validation of the proposed finite-state wake inflow modelling, along with the examination of identified models related to rotor loads, for a rotor in steady flight conditions subject to arbitrary perturbations.
      PubDate: 2016-12-22
      DOI: 10.1007/s13272-016-0235-y
       
  • Rotor performance enhancement via localized pitch control and its effects
           on hub vibrations and pitch link loads
    • Authors: Philip Küfmann; Rainer Bartels; Berend G. van der Wall
      Abstract: Abstract This paper presents an approach to enhance rotor performance and reduce vibration levels at the rotor hub by introducing local blade pitch variations at specific azimuthal locations. Two different variants of these “localized pitch control” (LPC) functions are presented and their effects both on rotor performance and vibrational loads are studied using parametric variation and subsequent numerical optimization of the respective LPC signals. The results are compared with those obtained from a conventional approach using 2/rev higher harmonic control (HHC). Numerical calculations were performed using the DLR’s comprehensive rotor code S4 with a modified Beddoes inflow-model simulating an isolated hingeless rotor at an advance ratio of µ = 0.382. In those simulations power reductions of up to 7.61 and 3.36% could be reached using two sets of different model rotor blades. Both for power reduction and simultaneous reduction of power and 4/rev vibrational loads, LPC performed slightly better than conventional 2/rev HHC but also resulted in higher actuation demands which have to be taken into account for real-world applications of LPC.
      PubDate: 2016-12-21
      DOI: 10.1007/s13272-016-0233-0
       
  • About the emissions of alternative jet fuels
    • Authors: Marina Braun-Unkhoff; Uwe Riedel; Claus Wahl
      Abstract: Abstract In the last years, several alternative aviation jet fuels have been approved as a response to worldwide concerns on adverse environmental effects of greenhouse gas emissions. However, comprehensive emissions studies are not part of the approval process. When burning a jet fuel, the exhaust gases are a mixture of gaseous specious including aromatics and non-gaseous species, particles, and soot. In addition, these species may affect the growth and lifetime of contrails known to be of influence on the climate due to their radiative forcing. Within this context, the use of synthetic aviation fuels may offer several advantages, going beyond reduced CO2 emissions. These issues were addressed by studying the combustion of synthetic jet fuels taking into account their individual composition. An overview of what is known on their emission pattern was presented. Mostly, the same general trends were reported for the emissions of interest, for the fuels considered and at the power settings selected, with no adverse emissions effects. In particular, less soot particle emissions were reported, in mass and in number concentration, for GtL, HEFA, and farnesane. Moreover, a strong link between the amount and type of aromatics content of a jet fuel and soot emissions was observed.
      PubDate: 2016-12-19
      DOI: 10.1007/s13272-016-0230-3
       
  • Fan casing contouring under consideration of aeroacoustics, mechanics,
           aeroelasticity, and whole engine performance
    • Authors: A.-L. Aulich; T. Sauer; S. Iseni; A. Moreau; D. Peitsch; R. Mailach; D. Micallef; L. Enghardt; E. Nicke
      Abstract: Abstract Aircraft propulsion will continue to rely on gas turbine technology for the next decades to come. Thus, to achieve environmental agreements, ensure engine safety, and retain economic competitiveness, ongoing development with a multidisciplinary design approach is indispensable. In the present study, the multi-criteria analysis of the fan, a decisive component in modern aero engines, is examined. In particular, the interaction of the fan blades with the fan casing is analyzed and an appropriate design approach, including automatic optimization, is used. As one part of the disciplines conjunction, an automated aeroacoustic approach is realized. The aerodynamic and acoustic fitness functions and constraints are based on Reynolds-Averaged Navier–Stokes (RANS) simulations of the fan stage. PropNoise, a fast analytical prediction tool for fan noise, is used. It has been under development since recent years and is already validated on several test cases. Preliminary studies have shown that the flow in the rotor tip region is a major contributor to the broadband noise emission. Based on this, the optimization process focuses on the variation of the casing contour around the fan blades. The impact of the modified flow field in the rotor tip region concerning the aeroelastic behavior is also investigated. As aeroelastic evaluation requires a high level of know-how and is very time consuming, it is linked to the optimization process chain by a discrete evaluation of selected members. This allows a simultaneous adjustment of the design in case of aeroelastic issues. Furthermore, the impact of the fan modifications regarding the overall engine performance is evaluated. Off-design cycle calculations allow incorporating such detailed studies in a global engine optimization.
      PubDate: 2016-12-08
      DOI: 10.1007/s13272-016-0226-z
       
  • The promised future of multi-core processors in avionics systems
    • Authors: O. Sander; F. Bapp; L. Dieudonne; T. Sandmann; J. Becker
      Abstract: Abstract Modern airplanes need to satisfy rising requirements in terms of functionality and fuel efficiency per passenger. Therefore, an ever-increasing amount of electronics is being integrated in the airplanes either by adding new functionalities or by exchanging mechanical systems by more complex and highly integrated mechatronic ones, optimizing the space, weight and energy used by the airplane infrastructure. Embedded computers are the base of this development and have to perform more and more tasks with at least the same safety characteristics as before. In the last 15 years, different functions traditionally realized in separated devices must be grouped together in one device to limit the ever-increasing number of computers in new airplanes. For safety reasons, this has only been done based on single-core processors up to now: the multi-core technology cannot insure the same level of confidence as single-core controllers—it was mainly invented to gain performance. But the performance of the current single-core processors adequate for embedded and safety–critical applications is limited and, therefore, restricts the grouping of applications. The automotive industry is confronted with similar but still stronger increasing performance challenges. In this sector, the multi-core processors are already considered as the only known solution to fulfill the rising requirements and are, therefore, expected to completely replace single-core processors in a few years. Specific multi-core processor architectures and functionalities improving safety capabilities have recently been developed. The goal of this contribution is to show how the avionics might benefit from using these safety-oriented automotive multi-core processors.
      PubDate: 2016-12-02
      DOI: 10.1007/s13272-016-0228-x
       
 
 
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