动能BGK格式模拟高雷诺数定常流的收敛性研究  

Improvement studies on convergence acceleration of gas-kinetic BGK scheme for high-Re stationary flows

作　　者：蒋瑾[1] 钱跃竑[1] 

机构地区：[1]上海大学上海市应用数学和力学研究所,上海200072

出　　处：《空气动力学学报》2012年第4期464-470,共7页Acta Aerodynamica Sinica

基　　金：教育部创新团队项目(IRT0844);上海市教委创新项目(08ZZ43);自然科学基金委杰出青年基金(10625210);上海大学研究生创新基金

摘　　要：为克服动能BGK格式计算耗时多、收敛慢的缺点,在格式中引入当地时间步长、隐式LU-SGS方法和多重网格技术,基于RAE2822翼型粘性跨声速绕流的数值模拟,对其收敛性的改善进行了研究。结果表明:上述3种加速手段对求解定常问题时的收敛性有明显的改善,达到定常解所需的迭代步数随着CFL数的提高而减少;因而求解某类问题时,隐式格式比显式格式更具优势;多重网格既适用于显式格式,也适用于隐式格式,加速性更加突出。In order to overcome the obvious drawback of gas-kinetic BGK scheme with its weak computational efficiency, three main convergence acceleration techniques, including local time stepping, implicit LUSGS method and multigrid, were adopted and tested. Based on simulation of viscous transonic steady flows over RAE2822 airfoil, their effectiveness was analyzed in detail. The following are the key results： 1. the speed-up to steady state is significant after acceleration techniques were employed; 2. as CFL number increased, needed steps for convergence is decreased; 3. multigrid is a very powerful tool and can be implemented for both explicit and implicit time-advancing methods. In this communication, the efficiency of 4-level Vcycle multigrid is the best one and its ratio of speed-up can reach 11 for explicit approach and nearly 9 for implicit scheme.

关 键 词：动能BGK格式 当地时间步长 隐式LU—SGS方法 多重网格 收敛性 定常流 

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]