SPH方法气-液界面边界条件研究  

On SPH Method with Treatment of Gas-Liquid Interface Boundary Conditions

作　　者：周杰[1] 徐胜利[1] 

机构地区：[1]清华大学航天航空学院,北京100084

出　　处：《计算物理》2017年第4期409-416,共8页Chinese Journal of Computational Physics

基　　金：博士后基金(2015M581081);中国运载火箭技术研究院基金(CALT201601);清华大学自主课题(20161080102)资助项目

摘　　要：针对界面附近粒子光滑函数截断和非物理穿透问题,提出一种气-液界面边界条件的处理方法.当界面附近支持域出现不同材料粒子,每步计算可在支持域设置虚粒子,按照密度分配方法给虚粒子物理量赋值,并对界面附近粒子引入气-液两相阻力.采用SPH方法和Level-Set方法,计算运动激波对气-液界面作用问题,两者计算结果一致,初步验证了气-液界面边界条件处理的适用性.用SPH方法分别计算超声速气流中的圆截面液柱绕流和下落问题,界面两侧粒子压力和法向速度连续,给出弓形激波、回流区和下游回流区等定性合理结果.表明本文方法可适度避免界面附近流体粒子光滑截断和粒子非物理穿透现象、界面附近流场数值振荡.To study truncation of an integral function and unphysical penetration of particles near an interface, treatment of boundary conditions at a gas-liquid interface was proposed based on concept of ghost fluid method（GFM）. Ghost particles are copied into kernel domain for avoiding truncation of integral function. Parameters are specified near interface for ghost particles according to density distribution method. Drags produced by slip velocity between particles of gas and liquid are included in computation. With comparison of results obtained by methods of SPH and level-set on shock wave interacting with a gas-liquid interface, acceptable numerical precision is shown since results are basically identical for calibration examples. Results are both obtained for cases of streaming around an initially fixed water cylinder and a fall-off of a water cylinder. The phenomena seem physically resasonable based on obtained results. Treatment of gas-liquid interface boundary condition approximately avoids truncation of an integral functions near interface and prevents numerical oscillation, particles penetration for SPH methodology. Pressure and normal velocity are kept continuously on both sides of gas-liquid interface during computation.

关 键 词：SPH GFM方法 激波 气-液界面 

分 类 号：V211.3[航空宇航科学与技术—航空宇航推进理论与工程]