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Publisher: Springer-Verlag   (Total: 2341 journals)

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Showing 1201 - 1400 of 2341 Journals sorted alphabetically
J. of Combinatorial Optimization     Hybrid Journal   (Followers: 5, SJR: 1.093, h-index: 34)
J. of Communications Technology and Electronics     Hybrid Journal   (Followers: 2, SJR: 0.29, h-index: 16)
J. of Community Genetics     Hybrid Journal   (Followers: 1, SJR: 0.727, h-index: 14)
J. of Community Health     Hybrid Journal   (Followers: 8, SJR: 0.921, h-index: 44)
J. of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology     Hybrid Journal   (Followers: 8, SJR: 1.087, h-index: 74)
J. of Comparative Physiology B : Biochemical, Systemic, and Environmental Physiology     Hybrid Journal   (Followers: 4, SJR: 1.126, h-index: 59)
J. of Compassionate Health Care     Open Access   (Followers: 2)
J. of Computational Analysis and Applications     Hybrid Journal   (SJR: 0.291, h-index: 19)
J. of Computational Electronics     Hybrid Journal   (Followers: 4, SJR: 0.511, h-index: 20)
J. of Computational Neuroscience     Hybrid Journal   (Followers: 24, SJR: 1.068, h-index: 60)
J. of Computer and Systems Sciences Intl.     Hybrid Journal   (SJR: 0.27, h-index: 13)
J. of Computer Science and Technology     Open Access   (Followers: 5, SJR: 0.437, h-index: 31)
J. of Computer Virology and Hacking Techniques     Hybrid Journal   (Followers: 6, SJR: 0.151, h-index: 2)
J. of Computer-Aided Molecular Design     Hybrid Journal   (Followers: 2, SJR: 0.995, h-index: 78)
J. of Computers in Education     Hybrid Journal   (Followers: 8)
J. of Computing in Higher Education     Hybrid Journal   (Followers: 13, SJR: 0.363, h-index: 21)
J. of Consumer Policy     Hybrid Journal   (Followers: 7, SJR: 0.704, h-index: 30)
J. of Contemporary Mathematical Analysis     Hybrid Journal   (SJR: 0.237, h-index: 5)
J. of Contemporary Physics (Armenian Academy of Sciences)     Hybrid Journal   (Followers: 11, SJR: 0.197, h-index: 6)
J. of Contemporary Psychotherapy     Hybrid Journal   (Followers: 5, SJR: 0.397, h-index: 23)
J. of Control Theory and Applications     Hybrid Journal   (Followers: 2, SJR: 0.359, h-index: 19)
J. of Control, Automation and Electrical Systems     Hybrid Journal   (Followers: 10, SJR: 0.231, h-index: 9)
J. of Crop Science and Biotechnology     Hybrid Journal   (Followers: 7)
J. of Cross-Cultural Gerontology     Hybrid Journal   (Followers: 5, SJR: 0.631, h-index: 29)
J. of Cryptographic Engineering     Partially Free   (Followers: 5, SJR: 0.989, h-index: 11)
J. of Cryptology     Hybrid Journal   (Followers: 2, SJR: 1.443, h-index: 55)
J. of Cultural Economics     Hybrid Journal   (Followers: 4, SJR: 0.539, h-index: 29)
J. of Database Marketing & Customer Strategy Management     Hybrid Journal   (Followers: 8, SJR: 0.149, h-index: 8)
J. of Derivatives & Hedge Funds     Hybrid Journal   (Followers: 8, SJR: 0.114, h-index: 5)
J. of Developmental and Physical Disabilities     Hybrid Journal   (Followers: 8, SJR: 0.574, h-index: 29)
J. of Digital Imaging     Hybrid Journal   (Followers: 10, SJR: 0.578, h-index: 35)
J. of Direct Data and Digital Marketing Practice     Hybrid Journal   (Followers: 8, SJR: 0.154, h-index: 6)
J. of Dynamical and Control Systems     Hybrid Journal   (Followers: 2, SJR: 0.4, h-index: 26)
J. of Dynamics and Differential Equations     Hybrid Journal   (SJR: 1.418, h-index: 31)
J. of Earth Science     Hybrid Journal   (Followers: 8, SJR: 0.483, h-index: 16)
J. of Earth System Science     Open Access   (Followers: 43, SJR: 0.448, h-index: 32)
J. of East Asian Linguistics     Hybrid Journal   (Followers: 6, SJR: 0.537, h-index: 20)
J. of Echocardiography     Hybrid Journal   (Followers: 4, SJR: 0.22, h-index: 3)
J. of Economic Growth     Hybrid Journal   (Followers: 27, SJR: 3.273, h-index: 63)
J. of Economic Interaction and Coordination     Hybrid Journal   (SJR: 0.263, h-index: 12)
J. of Economics     Hybrid Journal   (Followers: 17, SJR: 0.418, h-index: 23)
J. of Economics and Finance     Hybrid Journal   (Followers: 6, SJR: 0.272, h-index: 19)
J. of Educational Change     Hybrid Journal   (Followers: 7, SJR: 0.961, h-index: 21)
J. of Elasticity     Hybrid Journal   (Followers: 6, SJR: 0.851, h-index: 45)
J. of Electroceramics     Hybrid Journal   (SJR: 0.577, h-index: 57)
J. of Electronic Materials     Hybrid Journal   (Followers: 5, SJR: 0.609, h-index: 75)
J. of Electronic Testing     Hybrid Journal   (Followers: 2, SJR: 0.372, h-index: 27)
J. of Electronics (China)     Hybrid Journal   (Followers: 4, SJR: 0.112, h-index: 9)
J. of Elementary Science Education     Hybrid Journal   (Followers: 9)
J. of Engineering Mathematics     Hybrid Journal   (SJR: 0.347, h-index: 37)
J. of Engineering Physics and Thermophysics     Hybrid Journal   (Followers: 1, SJR: 0.288, h-index: 11)
J. of Engineering Research     Open Access   (Followers: 1, SJR: 0.145, h-index: 5)
J. of Engineering Thermophysics     Hybrid Journal   (Followers: 2, SJR: 0.763, h-index: 9)
J. of Environmental Studies and Sciences     Partially Free   (Followers: 2)
J. of Ethology     Hybrid Journal   (Followers: 2, SJR: 0.609, h-index: 25)
J. of Evolution Equations     Hybrid Journal   (SJR: 0.826, h-index: 26)
J. of Evolutionary Biochemistry and Physiology     Hybrid Journal   (SJR: 0.145, h-index: 11)
J. of Evolutionary Economics     Hybrid Journal   (Followers: 8, SJR: 0.492, h-index: 52)
J. of Experimental and Theoretical Physics     Hybrid Journal   (Followers: 3, SJR: 0.458, h-index: 39)
J. of Experimental Criminology     Hybrid Journal   (Followers: 42, SJR: 1.445, h-index: 28)
J. of Failure Analysis and Prevention     Hybrid Journal   (Followers: 5, SJR: 0.261, h-index: 15)
J. of Family and Economic Issues     Hybrid Journal   (Followers: 6, SJR: 0.396, h-index: 32)
J. of Family Violence     Hybrid Journal   (Followers: 35, SJR: 0.639, h-index: 56)
J. of Financial Services Marketing     Hybrid Journal   (Followers: 3, SJR: 0.273, h-index: 10)
J. of Financial Services Research     Hybrid Journal   (Followers: 22, SJR: 0.572, h-index: 36)
J. of Fixed Point Theory and Applications     Hybrid Journal   (SJR: 0.644, h-index: 13)
J. of Fluorescence     Hybrid Journal   (Followers: 3, SJR: 0.465, h-index: 56)
J. of Food Measurement and Characterization     Hybrid Journal   (SJR: 0.307, h-index: 4)
J. of Food Science and Technology     Hybrid Journal   (Followers: 6, SJR: 0.441, h-index: 29)
J. of Forest Research     Hybrid Journal   (Followers: 3, SJR: 0.495, h-index: 27)
J. of Forestry Research     Hybrid Journal   (Followers: 6, SJR: 0.304, h-index: 14)
J. of Fourier Analysis and Applications     Hybrid Journal   (Followers: 1, SJR: 1.18, h-index: 42)
J. of Friction and Wear     Hybrid Journal   (Followers: 7, SJR: 0.373, h-index: 7)
J. of Fusion Energy     Hybrid Journal   (Followers: 3, SJR: 0.387, h-index: 19)
J. of Gambling Studies     Hybrid Journal   (Followers: 6, SJR: 1.171, h-index: 57)
J. of Gastroenterology     Hybrid Journal   (Followers: 12, SJR: 1.651, h-index: 88)
J. of Gastrointestinal Cancer     Hybrid Journal   (Followers: 3, SJR: 0.304, h-index: 39)
J. of Gastrointestinal Surgery     Hybrid Journal   (Followers: 6, SJR: 1.64, h-index: 99)
J. of General Internal Medicine     Hybrid Journal   (Followers: 16, SJR: 1.804, h-index: 134)
J. of General Plant Pathology     Hybrid Journal   (SJR: 0.554, h-index: 22)
J. of Genetic Counseling     Hybrid Journal   (Followers: 5, SJR: 0.902, h-index: 39)
J. of Genetics     Open Access   (Followers: 4, SJR: 0.458, h-index: 28)
J. of Geodesy     Hybrid Journal   (Followers: 8, SJR: 2.173, h-index: 56)
J. of Geographical Sciences     Hybrid Journal   (Followers: 1, SJR: 0.8, h-index: 23)
J. of Geographical Systems     Hybrid Journal   (Followers: 4, SJR: 0.822, h-index: 39)
J. of Geometric Analysis     Hybrid Journal   (SJR: 1.491, h-index: 27)
J. of Geometry     Hybrid Journal   (Followers: 1, SJR: 0.272, h-index: 15)
J. of Global Optimization     Hybrid Journal   (Followers: 4, SJR: 0.992, h-index: 60)
J. of Global Policy and Governance     Hybrid Journal   (Followers: 10)
J. of Grid Computing     Hybrid Journal   (Followers: 1, SJR: 1.414, h-index: 37)
J. of Hand and Microsurgery     Hybrid Journal   (Followers: 1)
J. of Happiness Studies     Hybrid Journal   (Followers: 23, SJR: 0.881, h-index: 39)
J. of Hematopathology     Hybrid Journal   (Followers: 4, SJR: 0.2, h-index: 13)
J. of Heuristics     Hybrid Journal   (Followers: 5, SJR: 1.308, h-index: 50)
J. of High Energy Physics     Hybrid Journal   (Followers: 19, SJR: 1.052, h-index: 153)
J. of Homotopy and Related Structures     Hybrid Journal   (SJR: 0.232, h-index: 2)
J. of Housing and the Built Environment     Hybrid Journal   (Followers: 7, SJR: 0.648, h-index: 28)
J. of Huazhong University of Science and Technology [Medical Sciences]     Hybrid Journal   (SJR: 0.344, h-index: 19)
J. of Ichthyology     Hybrid Journal   (Followers: 3, SJR: 0.304, h-index: 10)
J. of Immigrant and Minority Health     Hybrid Journal   (Followers: 11, SJR: 0.759, h-index: 37)
J. of Inclusion Phenomena and Macrocyclic Chemistry     Hybrid Journal   (Followers: 1, SJR: 0.331, h-index: 46)
J. of Indian Council of Philosophical Research     Hybrid Journal  
J. of Indian Philosophy     Hybrid Journal   (Followers: 12, SJR: 0.127, h-index: 12)
J. of Indian Prosthodontic Society     Open Access   (Followers: 1, SJR: 0.164, h-index: 7)
J. of Industrial Microbiology and Biotechnology     Hybrid Journal   (Followers: 15, SJR: 0.966, h-index: 80)
J. of Industry, Competition and Trade     Hybrid Journal   (Followers: 8, SJR: 0.327, h-index: 15)
J. of Infection and Chemotherapy     Hybrid Journal   (Followers: 1, SJR: 0.673, h-index: 46)
J. of Information Technology     Hybrid Journal   (Followers: 54, SJR: 1.474, h-index: 55)
J. of Information Technology Teaching Cases     Hybrid Journal   (Followers: 9)
J. of Infrared, Millimeter and Terahertz Waves     Hybrid Journal   (Followers: 2, SJR: 1.25, h-index: 36)
J. of Inherited Metabolic Disease     Hybrid Journal   (Followers: 2, SJR: 1.389, h-index: 77)
J. of Inorganic and Organometallic Polymers and Materials     Partially Free   (Followers: 9, SJR: 0.338, h-index: 33)
J. of Insect Behavior     Hybrid Journal   (Followers: 9, SJR: 0.569, h-index: 39)
J. of Insect Conservation     Hybrid Journal   (Followers: 10, SJR: 0.872, h-index: 43)
J. of Intelligent and Robotic Systems     Hybrid Journal   (Followers: 2, SJR: 0.629, h-index: 43)
J. of Intelligent Information Systems     Hybrid Journal   (Followers: 1, SJR: 0.691, h-index: 43)
J. of Intelligent Manufacturing     Hybrid Journal   (Followers: 3, SJR: 1.397, h-index: 54)
J. of Interventional Cardiac Electrophysiology     Hybrid Journal   (SJR: 0.93, h-index: 43)
J. of Intl. Business Studies     Hybrid Journal   (Followers: 31, SJR: 4.208, h-index: 130)
J. of Intl. Entrepreneurship     Hybrid Journal   (Followers: 9, SJR: 0.549, h-index: 23)
J. of Intl. Migration and Integration / Revue de l integration et de la migration internationale     Hybrid Journal   (Followers: 13, SJR: 0.308, h-index: 13)
J. of Intl. Relations and Development     Hybrid Journal   (Followers: 20, SJR: 0.793, h-index: 22)
J. of Labor Research     Hybrid Journal   (Followers: 17, SJR: 0.394, h-index: 27)
J. of Logic, Language and Information     Hybrid Journal   (Followers: 7, SJR: 0.288, h-index: 25)
J. of Low Temperature Physics     Hybrid Journal   (Followers: 3, SJR: 0.531, h-index: 52)
J. of Machinery Manufacture and Reliability     Hybrid Journal   (Followers: 2, SJR: 0.203, h-index: 7)
J. of Mammalian Evolution     Hybrid Journal   (Followers: 5, SJR: 1.134, h-index: 37)
J. of Mammary Gland Biology and Neoplasia     Hybrid Journal   (Followers: 2, SJR: 2.252, h-index: 83)
J. of Management and Governance     Hybrid Journal   (Followers: 13, SJR: 0.805, h-index: 33)
J. of Management Control     Hybrid Journal   (Followers: 4, SJR: 0.605, h-index: 6)
J. of Marine Science and Application     Hybrid Journal   (Followers: 3, SJR: 0.439, h-index: 11)
J. of Marine Science and Technology     Hybrid Journal   (Followers: 3, SJR: 0.235, h-index: 19)
J. of Maritime Archaeology     Hybrid Journal   (Followers: 21, SJR: 0.228, h-index: 8)
J. of Market-Focused Management     Hybrid Journal   (Followers: 2)
J. of Marketing Analytics     Hybrid Journal   (Followers: 4)
J. of Material Cycles and Waste Management     Hybrid Journal   (Followers: 3, SJR: 0.449, h-index: 22)
J. of Materials Engineering and Performance     Hybrid Journal   (Followers: 22, SJR: 0.544, h-index: 40)
J. of Materials Science     Hybrid Journal   (Followers: 20, SJR: 0.836, h-index: 123)
J. of Materials Science : Materials in Electronics     Hybrid Journal   (Followers: 5)
J. of Materials Science : Materials in Medicine     Hybrid Journal   (Followers: 5)
J. of Mathematical Biology     Hybrid Journal   (Followers: 12, SJR: 1.011, h-index: 71)
J. of Mathematical Chemistry     Hybrid Journal   (Followers: 5, SJR: 0.497, h-index: 45)
J. of Mathematical Fluid Mechanics     Hybrid Journal   (Followers: 6, SJR: 1.22, h-index: 22)
J. of Mathematical Imaging and Vision     Hybrid Journal   (Followers: 4, SJR: 0.901, h-index: 53)
J. of Mathematical Modelling and Algorithms     Hybrid Journal   (Followers: 2, SJR: 0.414, h-index: 23)
J. of Mathematical Sciences     Hybrid Journal   (SJR: 0.272, h-index: 23)
J. of Mathematics Teacher Education     Hybrid Journal   (Followers: 15, SJR: 1.062, h-index: 20)
J. of Maxillofacial and Oral Surgery     Hybrid Journal   (Followers: 2)
J. of Mechanical Science and Technology     Hybrid Journal   (Followers: 6, SJR: 0.589, h-index: 26)
J. of Medical and Biological Engineering     Hybrid Journal   (Followers: 1, SJR: 0.387, h-index: 18)
J. of Medical Humanities     Hybrid Journal   (Followers: 22, SJR: 0.299, h-index: 18)
J. of Medical Systems     Hybrid Journal   (Followers: 1, SJR: 0.717, h-index: 44)
J. of Medical Toxicology     Hybrid Journal   (Followers: 4, SJR: 0.874, h-index: 28)
J. of Medical Ultrasonics     Hybrid Journal   (Followers: 2, SJR: 0.18, h-index: 13)
J. of Medicine and the Person     Hybrid Journal  
J. of Membrane Biology     Hybrid Journal   (Followers: 2, SJR: 0.738, h-index: 82)
J. of Micro-Bio Robotics     Hybrid Journal   (SJR: 0.28, h-index: 3)
J. of Microbiology     Hybrid Journal   (Followers: 8, SJR: 0.741, h-index: 43)
J. of Mining Science     Hybrid Journal   (Followers: 5, SJR: 0.317, h-index: 16)
J. of Molecular Evolution     Hybrid Journal   (Followers: 9, SJR: 0.952, h-index: 108)
J. of Molecular Histology     Hybrid Journal   (Followers: 2, SJR: 0.755, h-index: 48)
J. of Molecular Medicine     Hybrid Journal   (Followers: 16, SJR: 2.165, h-index: 113)
J. of Molecular Modeling     Hybrid Journal   (Followers: 4, SJR: 0.466, h-index: 50)
J. of Molecular Neuroscience     Partially Free   (Followers: 11, SJR: 0.988, h-index: 69)
J. of Mountain Science     Hybrid Journal   (Followers: 4, SJR: 0.418, h-index: 15)
J. of Muscle Research and Cell Motility     Hybrid Journal   (Followers: 1, SJR: 1.264, h-index: 55)
J. of Nanoparticle Research     Hybrid Journal   (Followers: 3, SJR: 0.583, h-index: 84)
J. of Natural Medicines     Hybrid Journal   (SJR: 0.602, h-index: 28)
J. of Near-Death Studies     Hybrid Journal   (Followers: 2)
J. of Nephrology     Hybrid Journal   (Followers: 4, SJR: 0.689, h-index: 55)
J. of Network and Systems Management     Hybrid Journal   (SJR: 0.466, h-index: 26)
J. of Neural Transmission     Hybrid Journal   (Followers: 2, SJR: 1.034, h-index: 86)
J. of Neuro-Oncology     Hybrid Journal   (Followers: 3, SJR: 1.274, h-index: 90)
J. of Neuroimmune Pharmacology     Hybrid Journal   (Followers: 1, SJR: 1.662, h-index: 45)
J. of Neurology     Hybrid Journal   (Followers: 15, SJR: 1.429, h-index: 105)
J. of NeuroVirology     Hybrid Journal   (Followers: 1, SJR: 0.979, h-index: 69)
J. of Nondestructive Evaluation     Hybrid Journal   (Followers: 9, SJR: 0.863, h-index: 27)
J. of Nonlinear Science     Hybrid Journal   (Followers: 1, SJR: 1.887, h-index: 42)
J. of Nonverbal Behavior     Hybrid Journal   (Followers: 5, SJR: 0.723, h-index: 47)
J. of Nuclear Cardiology     Hybrid Journal   (SJR: 1.024, h-index: 68)
J. of Nutrition, Health and Aging     Hybrid Journal   (Followers: 21, SJR: 0.919, h-index: 60)
J. of Obstetrics and Gynecology of India     Hybrid Journal   (Followers: 6, SJR: 0.214, h-index: 6)
J. of Occupational Rehabilitation     Hybrid Journal   (Followers: 15, SJR: 0.811, h-index: 51)
J. of Ocean Engineering and Marine Energy     Hybrid Journal   (Followers: 2)
J. of Ocean University of China (English Edition)     Hybrid Journal   (Followers: 1, SJR: 0.237, h-index: 11)
J. of Oceanography     Hybrid Journal   (Followers: 9, SJR: 0.796, h-index: 52)
J. of Ocular Biology, Diseases, and Informatics     Hybrid Journal   (SJR: 0.183, h-index: 11)
J. of Optical and Fiber Communications Reports     Hybrid Journal   (Followers: 3)
J. of Optics     Hybrid Journal   (Followers: 8, SJR: 0.214, h-index: 8)
J. of Optimization Theory and Applications     Hybrid Journal   (Followers: 4, SJR: 0.898, h-index: 65)
J. of Ornithology     Hybrid Journal   (Followers: 22)
J. of Orofacial Orthopedics / Fortschritte der Kieferorthopädie     Hybrid Journal   (SJR: 0.574, h-index: 33)
J. of Orthopaedic Science     Hybrid Journal   (Followers: 6, SJR: 0.708, h-index: 48)
J. of Paleolimnology     Hybrid Journal   (Followers: 5, SJR: 0.984, h-index: 64)
J. of Parasitic Diseases     Hybrid Journal   (Followers: 2, SJR: 0.298, h-index: 9)
J. of Pediatric Neuropsychology     Hybrid Journal   (Followers: 3)
J. of Pest Science     Hybrid Journal   (Followers: 2, SJR: 1.341, h-index: 28)
J. of Pharmaceutical Health Care and Sciences     Open Access  
J. of Pharmaceutical Innovation     Hybrid Journal   (Followers: 8, SJR: 0.524, h-index: 17)
J. of Pharmaceutical Investigation     Hybrid Journal   (SJR: 0.331, h-index: 6)

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Journal Cover Environmental Fluid Mechanics
  [SJR: 0.585]   [H-I: 29]   [5 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1573-1510 - ISSN (Online) 1567-7419
   Published by Springer-Verlag Homepage  [2341 journals]
  • Numerical simulations of intrusive gravity currents interacting with a
           bottom-mounted obstacle in a continuously stratified ambient
    • Authors: Jian Zhou; Subhas K. Venayagamoorthy
      Pages: 191 - 209
      Abstract: Abstract In this study, the flow dynamics of intrusive gravity currents past a bottom-mounted obstacle were investigated using highly resolved numerical simulations. The propagation dynamics of a classic intrusive gravity current was first simulated in order to validate the numerical model with previous laboratory experiments. A bottom-mounted obstacle with a varying non-dimensional height of \(\tilde{D}=D/H\) , where D is the obstacle height and H is the total flow depth, was then added to the problem in order to study the downstream flow pattern of the intrusive gravity current. For short obstacles, the intrusion re-established itself downstream without much distortion. However, for tall obstacles, the downstream flow was found to be a joint effect of horizontal advection, overshoot-springback phenomenon, and associated Kelvin-Helmholtz instabilities. Analysis of the numerical results show that the relationship between the downstream propagation speed and the obstacle height can be subdivided into three regimes: (1) a retarding regime ( \(\tilde{D}\) \(\approx \) 0–0.3) where a 30 % increase in obstacle height leads to a 20 % reduction in propagation speed, simply due to the obstacle’s retarding effect; (2) an impounding regime ( \(\tilde{D}\) \(\approx \) 0.3–0.6) where the additional 30 % increase in obstacle height only leads to a further (negligible) 5 % reduction in propagation speed, due to the accelerating effect of upstream impoundment and downstream enhanced mixing; and (3) a choking regime ( \(\tilde{D}\) \(\approx \) 0.6–1.0) where the propagation speed is dramatically reduced due to the dominance of the obstacle’s blocking effect. The obstacle thickness was found to be irrelevant in determining the downstream propagation speed at least for the parameter range explored in this study. The present work highlights the significance of topographic effects in stratified flows with horizontal pressure forcing.
      PubDate: 2017-04-01
      DOI: 10.1007/s10652-016-9454-3
      Issue No: Vol. 17, No. 2 (2017)
       
  • Numerical modeling of simultaneous tracer release and piscicide treatment
           for invasive species control in the Chicago Sanitary and Ship Canal,
           Chicago, Illinois
    • Authors: Zhenduo Zhu; Davide Motta; P. Ryan Jackson; Marcelo H. Garcia
      Pages: 211 - 229
      Abstract: Abstract In December 2009, during a piscicide treatment targeting the invasive Asian carp in the Chicago Sanitary and Ship Canal, Rhodamine WT dye was released to track and document the transport and dispersion of the piscicide. In this study, two modeling approaches are presented to reproduce the advection and dispersion of the dye tracer (and piscicide), a one-dimensional analytical solution and a three-dimensional numerical model. The two approaches were compared with field measurements of concentration and their applicability is discussed. Acoustic Doppler current profiler measurements were used to estimate the longitudinal dispersion coefficients at ten cross sections, which were taken as reference for calibrating the longitudinal dispersion coefficient in the one-dimensional analytical solution. While the analytical solution is fast, relatively simple, and can fairly accurately predict the core of the observed concentration time series at points downstream, it does not capture the tail of the breakthrough curves. These tails are well reproduced by the three-dimensional model, because it accounts for the effects of dead zones and a power plant which withdraws nearly 80 % of the water from the canal for cooling purposes before returning it back to the canal.
      PubDate: 2017-04-01
      DOI: 10.1007/s10652-016-9464-1
      Issue No: Vol. 17, No. 2 (2017)
       
  • Warm discharges in cold fresh water: 2. Numerical simulation of laminar
           line plumes
    • Authors: Alabodite M. George; Anthony Kay
      Pages: 231 - 246
      Abstract: Abstract The behaviour of a discharge of warm water upwards into a homogeneous body of cold fresh water was investigated by means of a numerical model. The discharge has a parabolic velocity profile, with Reynolds number \(Re=50\) , Prandtl number \(Pr=7\) and Froude number varied over the range \(0.2 \le {\rm Fr} \le 2.5\) . Water density is taken to be a quadratic function of temperature, so that an initially positively buoyant discharge will experience buoyancy reversal as it mixes with an ambient below the temperature of maximum density. The resulting plume has some similarities to a fountain resulting from injection of negatively buoyant fluid upward into a less dense ambient. The plume is initially symmetric, but then its head detaches as it approaches its maximum height. The detached head is denser than the fluid in the plume below it, and the interaction between the sinking head and the rising plume causes a sideways deflection; as this cycle is repeated, the plume displays side-to-side flapping motion and vertical bobbing. As Froude number is increased (i.e. buoyancy reduced) the growth of the plume becomes slower, but the plume eventually reaches a greater height. We obtain empirical power-law scalings for maximum height and time taken to reach that height as functions of Froude number; these scalings are simlar to those for fountains with a linear dependence of density on temperature in the very weak regime.
      PubDate: 2017-04-01
      DOI: 10.1007/s10652-016-9468-x
      Issue No: Vol. 17, No. 2 (2017)
       
  • Integrated modeling of single port brine discharges into unstratified
           stagnant ambient
    • Authors: I. K. Nikiforakis; A. I. Stamou; G. C. Christodoulou
      Pages: 247 - 275
      Abstract: Abstract An integrated model is presented for the calculation of the characteristics in the intermediate field region of brine discharges from reverse osmosis desalination plants into unstratified stagnant coastal waters. The model consists of the near field model Modified CorJet Model and the far field model, which are interconnected via a coupling algorithm. This algorithm has been developed to simulate the flow and concentration characteristics of negatively buoyant jets (NBJ) after their impingement on the bottom. The coupling method was developed to be active according to literature, however further work and investigation is needed to be applicable for NBJ discharged into other ambient environments and especially in cases where the background values of ambient flow and concentrations affect the NF values and vice versa. The integrated model was validated with data from the literature as well as with data from experiments conducted in this study showing a good agreement. The coupling algorithm was also compared to other coupling techniques used in the literature for NBJ discharges showing better estimations of the experimental data.
      PubDate: 2017-04-01
      DOI: 10.1007/s10652-016-9473-0
      Issue No: Vol. 17, No. 2 (2017)
       
  • Does the canopy mixing layer model apply to highly flexible aquatic
           vegetation? Insights from numerical modelling
    • Authors: Timothy I. Marjoribanks; Richard J. Hardy; Stuart N. Lane; Daniel R. Parsons
      Pages: 277 - 301
      Abstract: Abstract Vegetation is a characteristic feature of shallow aquatic flows such as rivers, lakes and coastal waters. Flow through and above aquatic vegetation canopies is commonly described using a canopy mixing layer analogy which provides a canonical framework for assessing key hydraulic characteristics such as velocity profiles, large-scale coherent turbulent structures and mixing and transport processes for solutes and sediments. This theory is well developed for the case of semi-rigid terrestrial vegetation and has more recently been applied to the case of aquatic vegetation. However, aquatic vegetation often displays key differences in morphology and biomechanics to terrestrial vegetation due to the different environment it inhabits. Here we investigate the effect of plant morphology and biomechanical properties on flow–vegetation interactions through the application of a coupled LES-biomechanical model. We present results from two simulations of aquatic vegetated flows: one assuming a semi-rigid canopy and the other a highly flexible canopy and provide a comparison of the associated flow regimes. Our results show that while both cases display canopy mixing layers, there are also clear differences in the shear layer characteristics and turbulent processes between the two, suggesting that the semi-rigid approximation may not provide a complete representation of flow–vegetation interactions.
      PubDate: 2017-04-01
      DOI: 10.1007/s10652-016-9482-z
      Issue No: Vol. 17, No. 2 (2017)
       
  • Alternating skimming flow over a stepped spillway
    • Authors: Pedro Lopes; Jorge Leandro; Rita F. Carvalho; Daniel B. Bung
      Pages: 303 - 322
      Abstract: Abstract The study of stepped spillways in laboratory scales has been essentially focused on two separated sub-regimes within skimming flow. In this paper we investigate the appearance of an unclassified alternating skimming flow regime in a 0.5 m wide stepped spillway which does not fit on these earlier definitions, and which does not occur in a 0.3 m wide spillway. Our aim is to explain the genesis of this unclassified flow which is visualised in the physical stepped spillway, by using 3D numerical modelling. Flow depths and velocities are measured using an ultrasonic sensor and Bubble Image Velocimetry in the wider flume (0.5 m). The numerical model is validated with the experimental data from the 0.5 m wide spillway. After validation, the channel width of the same numerical model is reduced to 0.3 m wide spillway in order to characterise (compare) the case without (with) alternating skimming flow. Both cases are solved using Reynolds-Averaged Navier–Stokes equations together with the Volume-of-Fluid technique and SST k- \(\omega\) turbulence model. The experimental results reveal that the alternating skimming flow regime is characterised by an evident seesaw pattern of flow properties over consecutive steps. In turn, the numerical modelling clarified that this seesaw pattern is due to the presence of a complex system of cross waves along the spillway. These cross waves are also responsible for a mass and momentum exchange in the transversal direction and for the formation of the alternating skimming flow in the spillway.
      PubDate: 2017-04-01
      DOI: 10.1007/s10652-016-9484-x
      Issue No: Vol. 17, No. 2 (2017)
       
  • Modeling and data assessment of longitudinal salinity in a low-gradient
           estuarine river
    • Authors: Peter Bacopoulos; Ethan J. Kubatko; Scott C. Hagen; Andrew T. Cox; Teddy Mulamba
      Pages: 323 - 353
      Abstract: Abstract Continuous data of vertical-profile salinity were analyzed for four stations located successively upriver in a macrotidal estuary, the lower St. Johns River (Northeast Florida, USA). The data analysis confirmed well-mixed salinity conditions in the river with at most 1.3 ppt of vertical variability at Dames Point (river km 20), where the main variations of salinity are along the longitudinal axis of the river. Given the well-mixed salinity conditions and dominant horizontal structure of salinity variations in the river, we present and apply a barotropic, two-dimensional modeling approach for hydrodynamic-salinity transport simulation in the lower St. Johns River. When properly forced by offshore surge, high-resolution wind fields and freshwater river inflows, the model replicated the salinity measurements remarkably well, including the separation into tidal and sub-tidal components. The data and model results show that, at times, offshore winds and surge can be more influential on longitudinal salinity variations than local winds over the river. We demonstrate the importance of using proper boundary conditions to force the model relative to the minimal sensitivity of the model to parameter adjustment of horizontal mixing and uncertainty-based perturbation of wind and inflow forcings.
      PubDate: 2017-04-01
      DOI: 10.1007/s10652-016-9486-8
      Issue No: Vol. 17, No. 2 (2017)
       
  • Simulation of exchange flow between open water and floating vegetation
           using a modified RNG k - ε turbulence model
    • Authors: Zhaowei Liu; Yongcan Chen; Yongyan Wu; Wenyong Wang; Ling Li
      Pages: 355 - 372
      Abstract: Abstract The paper focuses on the numerical simulation of the exchange flow between open water and floating vegetation, which plays an important role in maintaining the ecological balance by transporting nutrient matter. The simulation was conducted using a new solver developed upon OpenFOAM. A modified RNG k-ε turbulence model, which is expected to model both the high- and low-Reynolds number flows correctly, was used to determine the eddy viscosity. Several particular terms were added into the momentum equations and turbulence model equations to model the effects of vegetation and buoyancy. Among these terms, the term for the effect of vegetation in the ε-equation was re-modelled. The model was validated by properly predicting the profiles of mean velocity and turbulent kinetic energy for flows through suspended canopies. The density flow between open and vegetated water was simulated with the same conditions as those of the experiment conducted by Zhang and Nepf. The predicted results agreed well with the experimental data and provided more detailed information of such exchange flow. The convection between the root layer and the layer beneath the roots, which was not observed in the experiment, was observed in the numerical simulation.
      PubDate: 2017-04-01
      DOI: 10.1007/s10652-016-9489-5
      Issue No: Vol. 17, No. 2 (2017)
       
  • Direct measurements of the drag force over aligned arrays of cubes exposed
           to boundary-layer flows
    • Authors: Riccardo Buccolieri; Hans Wigö; Mats Sandberg; Silvana Di Sabatino
      Pages: 373 - 394
      Abstract: Abstract Wind tunnel measurements of the total drag force for aligned arrays of cubes exposed to two different boundary-layer flows at three flow velocities are discussed. The drag force for eight different building packing densities λ p (from 0.028 to 1) is measured with a standard load cell generating a novel dataset. Different λ p are reproduced by increasing the number of buildings on the same lot area; this represents a real situation that an urban planner is faced with when a lot area of a given (fixed) size is allocated to the development of new built areas. It is assumed that the surrounding terrain is uniform and there is a transition from a given roughness (smooth) to a new roughness (rough). The approaching flow will adjust itself over the new surface within a distance that in general may be larger than the horizontal length covered by the array. We investigate the region where the flow adjustment occurs. The wide range of packing densities allowed us to analyse in detail the evolution of the drag force. The drag force increases with increasing packing densities until it reaches a maximum at an intermediate packing density (λ p  = 0.25 in our case) followed by a slight decrease at larger packing densities. The value of the drag force depends on the flow adjustment along the array which is evaluated by introducing the parameter “drag area” to retrieve information about the drag distribution at different λ p . Results clearly suggest a change of the distribution of the drag force, which is found to be relatively uniform at low packing densities, while most of the force acts on first rows of the arrays at large packing densities. The drag area constitutes the basis for the formulation of a new adjustment length scale defined as the ratio between the volume of the air within the array and the drag area. The proposed adjustment length scale automatically takes into account the change in drag distribution along the array for a better parameterization of urban effects in dispersion models.
      PubDate: 2017-04-01
      DOI: 10.1007/s10652-016-9493-9
      Issue No: Vol. 17, No. 2 (2017)
       
  • Application of CFD modelling to air quality in Kuwait City
    • Authors: Meruyert Zhunussova; Martin Jaeger; Desmond Adair
      Pages: 395 - 413
      Abstract: Abstract High-resolution computational fluid dynamics (CFD) simulations have been performed to assess the dispersion of air pollutants (CO2) emanating from traffic in a busy street and in the vicinity of a complex configuration of buildings located in Salmiya, Kuwait City. New buildings are planned for this area, and the work here includes predictions for the dispersion of pollutants after the buildings’ completion. The CFD simulations are based on calculated CO2 concentration levels for traffic counts taken on location in Salmiya with the existing configuration of buildings. As the computer code used in this work has been evaluated previously, it will be applied here to predict with confidence any potential air pollution problem areas on the addition of the new buildings. It was found for very light wind, that the proposed new buildings help reduce pollution in the vicinity of residential buildings within the configuration of buildings, but as the wind becomes moderate to strong, there was a tendency for the pollutant to get trapped in the residential area. Results are given for both exceptionally high ambient temperatures and very light wind, which are not often reported in studies found in the literature.
      PubDate: 2017-04-01
      DOI: 10.1007/s10652-016-9497-5
      Issue No: Vol. 17, No. 2 (2017)
       
  • Interaction between waves and gravity currents: description of turbulence
           in a simple numerical model
    • Authors: Antonino Viviano; Rosaria E. Musumeci; Enrico Foti
      Abstract: Abstract Effects of surface waves on gravity current propagation are studied by means of a numerical model. The adopted modeling approach couples a Boussinesq-type of model for surface waves and a gravity current model for stratified flows. In particular two different turbulence closure models are introduced which take into account subgrid turbulence and an additional depth-constant eddy-viscosity. The turbulence parameters are calibrated by means of experimental data on the time evolution of the heavy front, obtained both in the absence and in the presence of regular surface waves. Velocity fields, heavy and light front position, shear stresses, vorticity and entrainment calculated by the model are analyzed. The turbulence closure which includes both uniform and Smagorinsky type eddy viscosity allows a better description of the actual gravity current propagation. In particular, the results highlight the fact that the presence of the oscillatory motion causes, simultaneously, a reduction in turbulence and an increase in the mixing of heavy and light fluids. Such a result is in agreement with the experimental observations.
      PubDate: 2017-04-18
      DOI: 10.1007/s10652-017-9527-y
       
  • Evaluation of existing equations for temporal scour depth around circular
           bridge piers
    • Authors: Manish Pandey; P. K. Sharma; Z. Ahmad; Umesh Kumar Singh
      Abstract: Abstract Scour is defined as the processes of removal of sediment particles from water stream bed by the erosive action of activated water, and also carries sediment away from the hydraulic structures. Scour is the main cause of pier failure. Numerous equations are available for estimating temporal and equilibrium scour depth. The present study describes the phenomenon of temporal scour depth variation at bridge piers and deals with the methods for its estimation. The accuracy of six temporal scour depth equations are also checked in this study. After graphical and statistical analysis, it was found that the relationship proposed by Oliveto and Hager (J Hydraul Eng (ASCE) 128(9):811–520, 2002) predicts temporal scour depth better than other equations. Three equations of equilibrium time of scour are also used for computing equilibrium time. Equilibrium time equation proposed by Choi and Choi (Water Environ J 30(1–2):14–21, 2016) gives better agreements with observed values.
      PubDate: 2017-04-17
      DOI: 10.1007/s10652-017-9529-9
       
  • Influence of a flooding event discharge on accretion in wetlands
    • Authors: T. Serra; A. Ros; C. Vergés; X. Casamitjana
      Abstract: Abstract Flooding events in wetlands transport sediment particles landwards and can increase accretion in some areas of the wetland or resuspend the sediment in other areas. In this study a flooding event with different water discharges was analyzed in a laboratory simulated wetland to determine the effect stem density has on particle trapping. The discharge that entered the simulated wetland was a particle laden barotropic current that initially produced a pulse that traveled through the wetland. After the first pulse, a baroclinic current, with a different timescale to the initial pulse, developed. Three stem densities, along with the ‘without plant case’, were considered. A semi-empirical model was formulated to explain the propagation of the water pulse. The model predicted the velocity of the pulse dampening in the presence of the simulated vegetation, by using the roughness parameter that had been found to increase with stem density. The baroclinic current propagated at a lower velocity than the pulse did, and its velocity decreased with stem density. As less sediment was found in the wetland with denser canopies, this indicates that the presence of a canopy acts as a barrier to sediment transportation. Furthermore, a greater amount of sediment was deposited in regions at the foot of the denser vegetated wetland zone and the sediment deposition also increased with the water discharge.
      PubDate: 2017-04-17
      DOI: 10.1007/s10652-017-9528-x
       
  • Compound channel flow with a longitudinal transition in hydraulic
           roughness over the floodplains
    • Authors: Victor Dupuis; Sébastien Proust; Céline Berni; André Paquier
      Abstract: Abstract Flows in a compound open-channel (two-stage geometry with a main channel and adjacent floodplains) with a longitudinal transition in roughness over the floodplains are experimentally investigated in an 18 m long and 3 m wide flume. Transitions from submerged dense vegetation (meadow) to emergent rigid vegetation (wood) and vice versa are modelled using plastic grass and vertical wooden cylinders. For a given roughness transition, the upstream discharge distribution between main channel and floodplain (called subsections) is also varied, keeping the total flow rate constant. The flows with a roughness transition are compared to flows with a uniformly distributed roughness over the whole length of the flume. Besides the influence of the downstream boundary condition, the longitudinal profiles of water depth are controlled by the upstream discharge distribution. The latter also strongly influences the magnitude of the lateral net mass exchanges between subsections, especially upstream from the roughness transition. Irrespective of flow conditions, the inflection point in the mean velocity profile across the mixing layer is always observed at the interface between subsections. The longitudinal velocity at the main channel/floodplain interface, denoted \(U_{int}\) , appeared to be a key parameter for characterising the flows. First, the mean velocity profiles across the mixing layer, normalised using \(U_{int}\) , are superimposed irrespective of downstream position, flow depth, floodplain roughness type and lateral mass transfers. However, the profiles of turbulence quantities do not coincide, indicating that the flows are not fully self-similar and that the eddy viscosity assumption is not valid in this case. Second, the depth-averaged turbulent intensities and Reynolds stresses, when scaled by the depth-averaged velocity \(U_{d,int}\) exhibit two plateau values, each related to a roughness type, meadow or wood. Lastly, the same results hold when scaling by \(U_{d,int}\) the depth-averaged lateral flux of momentum due to secondary currents. Turbulence production and magnitude of secondary currents are increased by the presence of emergent rigid elements over the floodplains. The autocorrelation functions show that the length of the coherent structures scales with the mixing layer width for all flow cases. It is suggested that coherent structures tend to a state where the magnitude of velocity fluctuations (of both horizontal vortices and secondary currents) and the spatial extension of the structures are in equilibrium.
      PubDate: 2017-04-08
      DOI: 10.1007/s10652-017-9525-0
       
  • Blockage of saline intrusions in restricted, two-layer exchange flows
           across a submerged sill obstruction
    • Authors: Alan Cuthbertson; Janek Laanearu; Magda Carr; Joel Sommeria; Samuel Viboud
      Abstract: Abstract Results are presented from a series of large-scale experiments investigating the internal and near-bed dynamics of bi-directional stratified flows with a net-barotropic component across a submerged, trapezoidal, sill obstruction. High-resolution velocity and density profiles are obtained in the vicinity of the obstruction to observe internal-flow dynamics under a range of parametric forcing conditions (i.e. variable saline and fresh water volume fluxes; density differences; sill obstruction submergence depths). Detailed synoptic velocity fields are measured across the sill crest using 2D particle image velocimetry, while the density structure of the two-layer exchange flows is measured using micro-conductivity probes at several sill locations. These measurements are designed to aid qualitative and quantitative interpretation of the internal-flow processes associated with the lower saline intrusion layer blockage conditions, and indicate that the primary mechanism for this blockage is mass exchange from the saline intrusion layer due to significant interfacial mixing and entrainment under dominant, net-barotropic, flow conditions in the upper freshwater layer. This interfacial mixing is quantified by considering both the isopycnal separation of vertically-sorted density profiles across the sill, as well as calculation of corresponding Thorpe overturning length scales. Analysis of the synoptic velocity fields and density profiles also indicates that the net exchange flow conditions remain subcritical (G < 1) across the sill for all parametric conditions tested. An analytical two-layer exchange flow model is then developed to include frictional and entrainment effects, both of which are needed to account for turbulent stresses and saline entrainment into the upper freshwater layer. The experimental results are used to validate two key model parameters: (1) the internal-flow head loss associated with boundary friction and interfacial shear; and (2) the mass exchange from the lower saline layer into the upper fresh layer due to entrainment.
      PubDate: 2017-03-23
      DOI: 10.1007/s10652-017-9523-2
       
  • Hydrodynamics and bed stability of open channel flows with submerged
           foliaged plants
    • Authors: M. X. Bao; C. W. Li
      Abstract: Abstract In this work we investigate experimentally and numerically the flow structure around foliaged plants deployed in a channel with gravels on the bed under submerged and barely submerged conditions. Velocity and Reynolds stress were measured by using a NORTEK Vectrino profiler. Visual observation shows that the initial motion of gravels is easier to be triggered under the condition of flow with barely submerged vegetation. This is confirmed by the measured velocity, Reynolds stress and total kinetic energy (TKE) profiles. The velocity exhibits a speed up in the near-bed region, and the associated Reynolds stress and TKE increase there. A 3D numerical model is then verified against the experiments and used to investigate systematically the effect of degree of submergence of foliaged plants on the channel bed shear stress. The results show that the maximum bed shear stress occurs when the foliage is situated slightly below the water surface, which can enhance channel bed instability.
      PubDate: 2017-03-18
      DOI: 10.1007/s10652-017-9524-1
       
  • Penetrative convection in slender containers
    • Authors: Suhas U. Pol; Harindra J. S. Fernando
      Abstract: Abstract An experimental study was conducted to investigate the penetration of a convective mixed layer into an overlying stably (solutally) stratified layer contained in a narrow, tall vessel when the fluid is subjected to a destabilizing heat flux from below. The interest was the evolution of the bottom mixed-layer height ( \(h\) ) with time ( \(t\) ) in the presence of side-wall effects, but without the formation of conventional double-diffusive layers. The side-wall effects are expected at small mixed-layer aspect ratios, \(\varGamma_{h} = (W/h)\) , where \(W\) is the container width. This case has not been studied hitherto, although there are important environmental and industrial applications. The mixed-layer growth laws for low aspect ratio convection were formulated by assuming a balance between the vertical kinetic energy flux at the interface and the rate of change of potential energy of the fluid system due to turbulent entrainment. The effects of sidewalls were considered using similarity arguments, by taking characteristic rms velocities to be a function of \(\varGamma_{h}\) , in addition to buoyancy flux ( \(q_{0}\) ) and \(h\) . In all stages of evolution, the similarity variables \(\xi = h/W\) and \(t^{\prime } = Nt/A\) , where \(A = N^{3} W^{2} /4q_{0}\) and \(N\) is the buoyancy frequency, scaled the mixed-layer evolution data remarkably well. Significant wall effects were noted when \(\varGamma_{h} < 1\) , and for this case the interfacial vertical turbulent velocity and length scales were identified via scaling arguments and experimental data.
      PubDate: 2017-03-15
      DOI: 10.1007/s10652-017-9522-3
       
  • Comparison of atmospheric modelling systems simulating the flow,
           turbulence and dispersion at the microscale within obstacles
    • Authors: S. Trini Castelli; G. Tinarelli; T. G. Reisin
      Abstract: Abstract Three different modelling techniques to simulate the pollutant dispersion in the atmosphere at the microscale and in presence of obstacles are evaluated and compared. The Eulerian and Lagrangian approaches are discussed, using RAMS6.0 and MicroSpray models respectively. Both prognostic and diagnostic modelling systems are considered for the meteorology as input to the Lagrangian model, their differences and performances are investigated. An experiment from the Mock Urban Setting Test field campaign observed dataset, measured within an idealized urban roughness, is used as reference for the comparison. A case in neutral conditions was chosen among the available ones. The predicted mean flow, turbulence and concentration fields are analysed on the basis of the observed data. The performances of the different modelling approaches are compared and their specific characteristics are addressed. Given the same flow and turbulence input fields, the quality of the Lagrangian particle model is found to be overall comparable to the full-Eulerian approach. The diagnostic approach for the meteorology shows a worse agreement with observations than the prognostic approach but still providing, in a much shorter simulation time, fields that are suitable and reliable for driving the dispersion model.
      PubDate: 2017-03-08
      DOI: 10.1007/s10652-017-9520-5
       
  • Mixing at a sediment concentration interface in turbulent open channel
           flow
    • Authors: Jorge S. Salinas; Mrugesh Shringarpure; Mariano I. Cantero; S. Balachandar
      Abstract: Abstract In this work we address the role of turbulence on mixing of clear layer of fluid with sediment-laden layer of fluid at a sediment concentration interface. This process can be conceived as the entrainment of sediment-free fluid into the sediment-laden layer, or alternatively, as the transport of sediment into the top sediment-free flow. This process is governed by four parameters—Reynolds number of the flow \(Re_\tau\) , non-dimensional settling velocity of the sediment (proxy for sediment size) \(\tilde{V}\) , Richardson number \(Ri_\tau\) and Schmidt number Sc. For this work we have performed direct numerical simulations for fixed Reynolds and Schmidt numbers while varying the values of Richardson number and particle settling velocity. In the simple model considered here, the flow’s momentum and turbulence pre-exists over the entire layer of fluid, while the sediment is initially confined to a layer close to the bed. Mixing of sediment-free fluid with the sediment-laden layer is associated primarily with upward transport of sediment and buoyancy. There is no simultaneous upward transport of fluid momentum and turbulence into the sediment-free fluid layer, which is already in motion and turbulent. The analysis performed shows that the ability of the flow to transport a given sediment size decreases with the distance from the bottom, and thus only fine enough sediment particles are transported across the sediment concentration interface. For these cases, the concentration profiles evolve to a final steady state in good agreement with the well-known Rouse profile. The approach towards the Rouse profile happens through a transient self-similar state. This behavior of the flow is not seen for larger particles. Detailed analysis of the three dimensional structure of the sediment concentration interface shows the mechanisms by which sediment particles are lifted up by tongues of sediment-laden fluid with positive correlation between vertical velocity and sediment concentration. Finally, the mixing ability of the flow is addressed by monitoring the time evolution of the center of mass of the sediment-laden layer and the vertical location of the sediment-free/sediment-laden interface.
      PubDate: 2017-03-08
      DOI: 10.1007/s10652-017-9521-4
       
  • A two-dimensional inviscid model of the gravity-current head by Lagrangian
           block simulation
    • Authors: Vincent H. Chu; Wihel Altai
      Abstract: Abstract A two-dimensional inviscid model of the gravity-current head produced by the release of a relatively small volume of dense fluid from behind a tall lock gate is constructed by Lagrangian block simulation. Three numerical experiments are conducted for the lock’s height-to-length aspect ratios H/L o  = 8, 4 and 2. The front speeds obtained by the simulations agree with the laboratory observation for a similar range of aspect ratios. The floor velocity in the wake behind these heads is found to be greater than their front speed. The high floor velocity is caused by the impingement of the coherent wake vortex on the floor. It is a condition that permits these gravity-current heads to maintain their structural integrity so that the fine sediments can travel with the head over long distances on the ocean floor. The structural coherence of the current head depends on the lock aspect ratio. The gravity-current head produced by the release from the lock with the highest aspect ratio of H/L o  = 8 is most coherent and relatively has the greatest floor velocity and the least trailing current behind the head.
      PubDate: 2017-03-07
      DOI: 10.1007/s10652-017-9519-y
       
 
 
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