沙粒跃移运动的数值模拟

The numerical simulation of sand particles saltation

沙粒在风场作用下形成的风沙运动,直接导致一系列环境问题。现有的数值模拟并没有揭示风沙流的二维性质。本文提出一种合理有效的模拟方法来揭示风沙流时空的变化。气相运动采用大涡模型,而固相(沙粒)处理为离散体系(DEM),并利用已有的沙粒与床面碰撞的激溅函数,以获得整个风沙系统运动特性。结果表明:其发展过程与以往的试验结果相比较符合;风沙流达到稳定后,不同截面输沙率沿高度分布与平均输沙率相比差别很大,并大约在9cm高处,平均输沙率出现极值,单宽输沙率沿风向分布同样具有非均匀性。

The movement of sand particles blown by wind,may cause many environment problems.At present the experimental research and theoretic research cannot reveal the two-dimension character of blown-sand flow.This paper presents a way in effect and in reason aiming to this aspect.The gas-phase treat with the large eddy simulation(LES),the solid-phase(sand particles) be dealt with discrete element method(DEM).The splash function replace the process of particles impact sand bed.The result shows that the growth of wind-blown sand movement confirms the experiment result.The mass flux verse height is different with average value in different section at steady state.About 9cm above sand bed,the value is max.