Modelling of intense collisional sediment transport with turbulent suspension

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Solid-liquid flows in geomorphological and industrial processes transport grains which are often supported by a combination of mutual collisions and turbulent suspension. A dominating support mechanism depends primarily on grain size and on local position in a layered structure of the solid-liquid flow. The proposed project deals with flows in which some grains are suspended by turbulent eddies of carrying liquid and the rest is transported as collisional bed load. We focus on steady-state uniform open-channel flow with monodisperse or bimodal sediment. Results of our previous research on purely collisional flows will be exploited to theoretically and experimentally describe the flow internal structure and its impact on the sediment discharge and open-channel friction/capacity. Granular rheology based approaches, including the kinetic theory, will be employed to formulate a mathematical model and its numerical solver. Model predictions of the flow internal structure and flow integral quantities will be calibrated and validated by experiments in a laboratory tilting flume. The goal of the project Theoretical and experimental description of internal structure of open-channel flow with combined bed+suspended load above mobile bed. Effect of flow structure on sediment discharge, channel resistance and capacity based on granular flow rheology. Mathematical model and its numerical solution.