Turbulent mechanisms in open channel sediment-laden flows |
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| Institution: | 1. State Key Laboratory of Hydroscience and Engineering, Tsinghua Univ., Beijing, 100084, China;2. State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, 810016, China;3. Virginia Institute of Marine Science, College of William & Mary, Center for Coastal Resource Management, Gloucester Point, VA, 23062, USA;1. Faculty of Geology, VNU University of Science, Vietnam National University, Hanoi 334 Nguyen Trai, Thanh Xuan, Hanoi, Viet Nam;2. Faculty of Marine and Coastal Engineering, Thuyloi University, 175 Tay Son, Dong Da, Hanoi, Vietnam;3. SedTrend Analysis Limited, 7236 Peden Lane, Brentwood Bay, BC, Canada V8M1C5;4. Faculty of Meteorology, Hydrology and Oceanography, VNU University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai, Thanh Xuan, Hanoi, Vietnam;1. Department of Civil and Environmental Engineering, University of California, Davis, 2001 Ghausi Hall, One Shields Ave., Davis, CA 95616, United States;2. Facultad de Ingeniería y Ciencias Aplicadas, Universidad de los Andes, Monseñor Alvaro del Portillo 12455, Las Condes, Santiago, Chile;3. Department of Civil Engineering, Universidad Andres Bello, Santiago 8320000, Chile;1. Deltares, Boussinesqweg 1, 2629 HV Delft, The Netherlands;2. U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA;3. Ghent University, Technologiepark 68 905, B-9052 Zwijnaarde, Belgium;4. Leovanrijn-Sediment-Consultancy, Domineeswal 6, 8356 DS Blokzijl, The Netherlands;1. Department of Civil Engineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan;2. Geo-Informatics Center, Asian Institute of Technology, Pathumthani 12120, Thailand;3. Key laboratory of River and Coastal Engineering, Vietnam Academy of Water Resources, Hanoi, Vietnam |
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| Abstract: | The effects of turbulence on water-sediment mixtures is a critical issue in studying sediment-laden flows. The sediment concentrations and particle inertia play a significant role in the effects of turbulence on mixtures. A two-phase mixture turbulence model was applied to investigate the turbulence mechanisms affecting sediment-laden flows. The two-phase mixture turbulence model takes into account the complicated mechanisms arising from interphase transfer of turbulent kinetic energy, particle collisions, and stratification. The turbulence in sediment-laden flows is the result of the interaction of four factors, i.e. the production, dissipation, diffusion, and inter-phase transfer of turbulent kinetic energy of mixtures. The turbulence production and dissipation are two dominant processes which balance the turbulent kinetic energy of mixtures. The turbulence production represents turbulence intensity, while the inter-phase transfer of turbulent kinetic energy denotes the effect of particles on the turbulence of sediment-laden flows. Although, the magnitude of the inter-phase interaction term is much less than that of the turbulence production and dissipation terms, due to an approximate local balance between production and dissipation of the turbulent kinetic energy, even the small order of the inter-phase interaction has a significant impact on the turbulent balance of sediment-laden flows. The presence of particles plays a duel role in the turbulence dissipation of mixtures: both promotion and suppression. An important parameter used to determine the turbulent viscosity of mixtures, which is constant in clear water, is the function of the sediment concentration and particle inertia in sediment-laden flows. |
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| Keywords: | Turbulence modulation Two-phase mixture turbulence model Suspended sediment Open channels |
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