中文摘要：

本文采用直接数值模拟（DNS）方法研究了气固两相三维圆柱绕流的涡量场和颗粒扩散，并着重讨论了圆柱绕流中卡门涡街的形成和涡结构的转捩过程。同时分析了圆柱绕流中不同Stokes数的颗粒在涡结构作用下的横向扩散。结果显示Stokes数为1的颗粒主要分布在流场大尺度涡结构的外边界，而Stokes数为0．01的颗粒在涡结构的作用下，在流场中充分混合。

英文摘要：

Direct Numerical Simulation has been used in this paper to study the transition ot flow field and dispersion characteristic of particles in a thee-dimensional cylinder wake, and discussed the effect of large- scale vortexes to dispersion of particles. Based on the flow field results, we use one-coupling methods to study the mixing and the dispersing behaviors field of the particles in typical sizes in the gas-solid two-phase cylinder wake. We found that the particles whose St=0.01 completely reproduce the vorticity field, and whose St=l exhibit special dispersing rules, i.e. distributing uniformly around the vortex kernel.