含有大位移动边界的复杂流场的数值模拟

含有运动弹丸的膛口流场是典型的大位移动边界问题,同时弹丸在出膛过程中,流场的结构也会发生变化,增加了流场的复杂程度.在对该流场的数值模拟中,将它分为两个区:弹丸运动区和普通流场区,它们之间用一个特殊的分区边界联系,同时运用网格局部重构技术处理弹丸运动造成的网格变形问题,并将对称轴定义为网格变形边界,使得弹丸在对称轴上运动过程中不会导致对称轴上的网格体积为负.从计算结果可以看出整个膛口波系结构变化过程和弹丸先加速后减速的过程,从而表明该动网格处理方法是成功的.

Simulation of Complex Flows with Large-scale Moving Boundaries

Complex flow with large-scale moving boundaries is divided into a moving boundary zone and a common flow zone connected by a special interior boundary named zone interface.Local remeshing method is applied to deal with grid-reforming of a high-speed bullet. The axis is defined as a special grid-deforming boundary to avoid negative volume of grid near the axis.Arbitrary Lagrangian-Eulerian(ALE) formulation is used to solve unsteady process of a bullet leaving a muzzle.It indicates that the bullet is accelerated and then decelerated gradually.