有限空间风沙流动数值模拟及边界条件问题

Numerical simulation of wind-sand current and boundary conditions in a limited space

采用Euler方法的双流体模型和颗粒动理学方法对二维风沙气固两相流动进行了数值模拟,研究不同边界条件下的气固两相速度与浓度分布以及进口条件下的风沙流动。结果表明,对边界为固体壁面的流动,沙粒边界条件对其浓度分布有严重的影响,必须计及能量平衡和沙粒速度滑移效应,体现为沙面上的沙粒起动和碰撞特性;进口效应的存在使得在较短的距离内不能获得合理的流动结构,要求根据实验给出准确的进口条件,或者计算域有足够的长度,使流动结构不受进口效应的影响。

Aeolian sand transport was simulated as a dense gas-solid two-phase flow in a limited two-dimensional space. The two-fluid model and the kinetic theory of granular medium were used to study the two-phase velocity and sand distributions for different inlet conditions. The results show that for wall boundary flow, the boundary condition for the sand particles has a serious effect on the sand distribution, so the energy transfer and the slip between the sand particles and the sand must be considered to balance the generation and dissipation of the impulsive motion energy due to the sand particle acceleration and collisions. The inlet effects result in a unrealistic flow structure near the inlet with a long development zone required to remove the influence of the inlet.