多弛豫时间格子波尔兹曼方法的分块算法  

Multi-block scheme of MRT lattice Boltzmann method for viscous fluid flow

作　　者：杨帆[1,2] 施徐明[1] 郭雪岩[1] 陈铁军[2] 吴玉林[2] 

机构地区：[1]上海理工大学能源与动力工程学院,上海200093 [2]清华大学水沙科学与水利水电工程国家重点实验室,北京100084

出　　处：《排灌机械工程学报》2013年第1期56-60,共5页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金资助项目(10902070;51176127;51106099)

摘　　要：为了进一步提高格子波尔兹曼方法计算效率,对"多弛豫时间"格子波尔兹曼方法的分块算法进行了研究,通过适当的处理来耦合各分块区域之间的计算,以满足界面处质量、动量及应力的连续,并保证物理时间上的同步.采用该算法对雷诺数为100时两平板间二维偏置圆柱绕流非定常流动进行了数值模拟.计算中分为2个区,将圆柱附近区域网格加密,就粗细网格间距比值为1,2,4,8共4种情况分别进行了计算,得到了圆柱附近涡量分布图与圆柱阻力和升力系数.计算结果表明:随着圆柱附近局部网格密度的增加,流场中存在于圆柱前驻点附近的非物理振荡现象得到了显著的消除;当网格密度达到一定程度后,计算所得圆柱阻力和升力系数与基准解的吻合程度令人满意,从而验证了该算法的有效性.In the last 20 years or so, there has been rapid progress in developing the lattice Boltzmann method （I,BM） for solving a variety of fluid dynamic problems. Compared with the single relaxation time （SRT） collision model, the multiple relaxation time （MRT） one has better computational stabili- ty. In order to obtain a high resolution near a solid body, a multi-block scheme is developed for the MRT lattice Boltzmann method. The interthce conditions are derived to make sure the continuity of mass, momentum and stresses across the interface between any two blocks can be satisfied. Further a temporal interpolation at an interface is also performed to ensure information at correct time level to be used. For validation the numerical simulations of the unsteady flows past a circular cylinder at Re = 100 was carried out. It was showed that the spatial oscillations in the regions with large velocity or pressure gradients such as stagnation point are suppressed in a great deal with increasing grid resolution, and the predicted drag and lift coefficients agree well with the benchmark data.

关 键 词：格子波尔兹曼方法 多弛豫时间 分块算法 网格加密 圆柱绕流 

分 类 号：S277.9[农业科学—农业水土工程] TK123[农业科学—农业工程]