改进粒子水平集法及其应用

针对传统粒子水平集方法的缺陷提出一种虚拟粒子对距离函数的修正方法.改进算法针对虚拟粒子与待修正网格点的各种相对位置进行误差修正,可以避免虚拟粒子在非界面法线方向移动而产生的误差.数值求解涡旋流场问题显示:改进算法的界面捕捉性能得到显著提高.在此基础上,结合投影法求解Navier-Stokes方程组,数值模拟存在高密度比(10³量级)及粘性比(10²量级)的不可压缩两相流问题(气泡上升及自由面不稳定性问题).计算结果与已有结果吻合良好,详细分析主要控制参数对瑞利-泰勒不稳定性现象的影响.

An Improved Particle Level Set Method and Its Application

An improved particle level set method is proposed for simulation of incompressible two-phase flows. In this method, an improved particle correction method is developed to deal with relative positions between escaped particles and grid corner, which reduces disturbance arising in distance function correction due to non-normal direction movement of escaped particles. The method is validated with capturing accurately moving interface in single vortex flow problem. A projection method is used to solve control equations of incompressible two-phase flows with high density ratio (nearly 10³) and viscosity ratio (nearly 10²). Six typical bubble shapes are successfully captured in simulation of rising bubbles. Finally, time-dependent evolution of Rayleigh-Taylor instability (RTI) interface is numerically investigated. Numerical results are in good agreement with published results. Effects of control parameters on evolution of RTI are well examined.