稀疏两相湍流的惯性颗粒倾向性弥散

气相采用大涡模拟、颗粒相采用拉格朗日轨道模型的方法对后台阶突扩流、充分发展槽道流和圆湍射流3种典型的稀疏气固两相流动进行了数值模拟，研究了颗粒倾向性弥散的特征和规律. 研究表明颗粒的跟随性和倾向性相联系，颗粒惯性和大涡结构同时决定颗粒的倾向性分布特征. Stokes数量级为1(气相时间参考尺度取为宏观特征时间尺度)左右的颗粒，倾向性分布特征最强烈. 颗粒倾向分布于低涡量(或是低脉动速度)的湍流区域. 

INERTIA PARTICLE PREFERENTIAL DISPERSION IN DILUTE TWO-PHASE TURBULENT FLOWS

Preferential dispersion of the particles was numericallystudied in three types of turbulent flows, namely, the flow over abackward-facing step, the fully developed channel flow and the round jetflow. Gas-phase was simulated by means of large eddy simulation andparticle-phase was tracked by particle trajectory model. It's shown thatinertia particles have preferential dispersion in the three turbulent flows,and the property of preferential motion of the particles is related to theparticle following property. The particle preferential dispersions aredetermined both by particle inertia and by large eddy structures. Particleswith Stokes number in the order of magnitude 1 (based on the macrotime-scale of fluid flow) have the strongest preferential distribution inlarge scale structures and they tend to accumulate in the turbulent regionswith low vorticity or low fluctuating velocity.