串列对转双圆柱的多块LB模拟

Multi-Block Lattice Boltzmann Method for Flows Around two Tandem Rotating Circular Cylinders

结合格子玻尔兹曼方法(Lattice Boltzmann Method,简称LBM)和多块网格(Multi-Block Grid)技术,数值研究较小雷诺数(Re=100)下均匀来流绕串列对转双圆柱问题,综合分析圆柱中心间距比S/D和圆柱无量纲旋转速度α对流场结构的影响,考察前、后圆柱的涡脱落形态和升阻力特性.结果表明:当间距比为1.2时存在一临界旋转比αc,转速超过这一值后前圆柱产生负Magnus效应;间距比为2时,流场出现类似单旋转圆柱时的第二不稳定模态;当间距比较大(S/D=4、6)时,前、后柱之间存在涡脱落,后柱尾涡中出现2S、2S*、2P、P+S等多种形态.

Flows past a pair of rotating circular cylinders in tandem arrangement at Re = 100 are studied numerically. Multi-block lattice Boltzmann method （ LBM ） is used. Basic features of vortex shedding and forces acting on rotating circular cylinders are studied with comprehensive analysis of impact of cylindrical center spacing ratio S/D and rotational speed a . There exists a critical rotating speed at S/D = 1.2, exceeding which the former cylinder produces a negative Magnus lift; As S/D = 2, flow field emerges a second unstable mode similar to a single rotating cylinder; At relative large spacings（S/D = 4,6） , vortex sheds between cylinders. Wake flows of the later cylinder present a variety of forms of 2S,2S＊ ,2P,P ＋ S and so on.