带自由表面水流与离散颗粒耦合模型研究

摘要

In order to investigate the sediment transportation by means of numerical simulating particles' motion,a numerical model coupling of CFD and DEM is established in this paper.The codes in-house is based on Fortran.There are two types of particle collision modes established in the present numerical model,i.e.the rigid particle mode and the soft particle mode.To verify the numerical model,two study cases were carried out.One is about the free falling motion of a single spherical particle in the still water, and the another one is about the motion of well mixed particles with different density initially in the still water.With the well validation,the present numerical model is confirmed to be feasible in the research of sediment motion with the mesosopic view.%基于考察泥沙运动的细观行为特征，采用离散单元法(DEM)模拟泥沙颗粒运动，结合带自由表面的水动力学计算模型，建立了CFD-DEM耦合数值模型。计算程序开发基于 Fortran语言来实现。耦合模型中实现了硬球模型和软球模型两种颗粒碰撞模型，应用范围较广。作为自由表面水流与泥沙颗粒流数值模型的初步研究，在模型建立的基础上，对模型做了基本的验证。分别通过单颗粒静水沉降和混合颗粒群分选两个计算工况，验证了模型的正确性及模拟精度。该耦合模型可进一步丰富带自由表面水流条件下泥沙运动的研究手段。