Effect of oscillation of ambient flow on particle motion

采用基于标记和单元（MAC）方法的三维直接数值模拟（DNS）方法，对均匀流向振荡流中刚性球所受的流体力进行了数值研究。在颗粒雷诺数为1 < Rep < 100的区域内，将标准阻力、附加质量力、压力梯度力和历史力相加，得到了常规的阻力表达式，（马克西&莱利1983 ;奥顿、亨特和普鲁德霍姆1988 ; Kim，Elghobashi & Sirignano 1998）与DNS关于振荡流中刚性球体上阻力的结果非常一致。在Rep>300的高颗粒雷诺数区域，传统的流体力表达式不能预测旋涡脱落对流体力的影响。

The fluid force acting on a rigid sphere in a uniform streamwise oscillating flow was numerically investigated by means of a three-dimensional direct numerical simulation (DNS) based on a marker and cell (MAC) method. In the particle Reynolds number region of 1 < Rep < 100, the conventional expression of drag force summing the standard drag, added mass force, pressure gradient force and history force (Maxey & Riley 1983 ; Auton, Hunt & Prud'homme 1988 ; Kim, Elghobashi & Sirignano 1998) is in good agreement with the DNS results of the drag force on a rigid sphere in an oscillating flow. In the high particle Reynolds number region of Rep>300, the conventional expression of fluid force cannot predict the effect of vortex shedding on the fluid force.