A numerical study of the impacts of sediment composition on debris flows  

作　　者：Abiola Abraham Adebiyi Peng Hu 

机构地区：[1]Institute of Port,Coastal,and Ofshore Engineering,Ocean College,Zhejiang University,Zhoushan 316021,China

出　　处：《Journal of Hydrodynamics》2022年第4期620-633,共14页水动力学研究与进展B辑（英文版）

基　　金：the National Natural Science Foundation of China(Grant Nos.12172331,11872332);the Natural Science Foundation of Zhejiang(Grant No.LR19E090002);the HPC Center of Zhejiang University(Zhoushan Campus).

摘　　要：Debris flows in their natural environments are made up of different sediment sizes,even though they are often considered to be uniform in numerical studies.This prompted the present study to investigate the behaviors of debris flows with nonuniform sediment composition.A model is developed to investigate nonuniform debris flows and the characteristic behavior of their compositions.The model’s framework of mass and momentum equations and mass exchange with the bed are solved using the shock-capturing finite volume method.The model is first tested with a uniform sediment laboratory experiment,where there is a good agreement.The model is then tested against two flume experiments with different bed water content and porosity.The model performed well in both cases,however,the slight underprediction in the second case can be associated with the complexity of debris flows which may not be fully captured by physical equations.The model is further used to investigate different compositions of debris flows including mixed grain sizes,mean size,fine and coarse sediment size,and no erosion/deposition.The modeling of the mixed grain sizes produced a more accurate result,and this justifies the consideration of nonuniform sediment sizes in the numerical studies of debris flows.To enhance the understanding of frontal coarsening and rear fining in experimental debris flow,the model is also used to investigate cases with different sediment compositions,and the model was able to reproduce the frontal coarsening and rear fining observed in experiments.

关 键 词：Debris flows numerical modeling finite volume method(FVM) sediment composition EROSION debris coarsening 

分 类 号：TV142[水利工程—水力学及河流动力学] O351.2[理学—流体力学]