中文摘要：

为了考察颗粒在圆柱尾流中扩散的运动机理，对气固两相圆柱尾迹流动进行了高精度紧致差分方法的三维直接数值模拟．在对气相流场进行高精度模拟的基础上，采用了Lagrangrian方法来追踪颗粒场的运动．比较了不同颗粒Stokes数为0．01、1、10和不同Reynolds数为180和200下颗粒的扩散函数，考察了三维圆柱尾迹流流场中气相场的运动对颗粒相扩散的影响．模拟结果表明：当气相流场由二维特性向三维特性转变时，由于受到气流场展向涡的影响，颗粒的展向扩散函数有相当程度的增大．颗粒在横向上扩散函数随着粒径的增大而增大，而在展向上颗粒扩散函数则随着粒径的增大而减小．

英文摘要：

In order to investigate the mechanism of the particle dispersion in circular cylinder wake flow, gas-solid two phase wake flow of the circular cylinder was directly simulated using high accuracy compact finite difference method in three dimensions. Based on the high accuracy gas-phase field simulation, motion of the particle field was traced employing Lagrangian method. The particle dispersion functions with different particle Stokes numbers of 0.01,1,10 and Reynolds numbers of 180 and 200 were compared, and the influence of gas phase field motion on particle dispersion in three-dimensional circular cylinder wake was investigated. The simulation results show that when the gas phase flow field transits from two dimensions characteristic to three dimensions characteristic, the spanwise particle phase dispersion function increases greatly with the effect of the spanwise vortex in the gas flow field. The transverse particle dispersion function increases with the increasing particle size, but the spanwise particle dispersion function decreases with the increasing particle size.