基于LBM方法的钝体绕流数值模拟

Numerical Simulation of the Flow around a Blunt Body Based on LBM Method

在生活中高雷诺数的钝体绕流现象普遍存在,但准确计算其流场特性却并不容易。针对这一问题采用多松弛时间格子Boltzmann方法(LBM)与壁面自适应局部涡黏(WALE)模型相结合的方法(MRT-LBM-WALE),对定常流下雷诺数90 000的二维圆柱绕流进行数值模拟,同时应用增强壁面函数对壁面附近湍流黏性进行修正,测算了其阻力系数、升力系数、涡脱落频率和表压。计算结果与已有实验比较表明,阻力系数、升力系数以及涡街的脱落频率均跟实验值吻合较好,同时在涡街捕捉上也表现出较高的稳定性和精度。

The flow around a blunt body at high Reynolds number is a common phenomenon. But it is not easy to calculate the flow characteristics accurately. The lattice Boltzmann method （LBM） of multiple-relaxation-time with Wall adapting local eddy-viscosity（WALE） model（MRT-LBM-WALE） is used to explore the flow around a two-dimensional cylinder at a Reynolds number of 90000, and enhanced wall function is used to adjust the turbulent viscosity near the wall. The drag coefficient, lift coefficient,vortex shedding frequency and surface pressure are calculated. The results show that the MRT- LBM-WALE method is more elaborate and stable in capturing vortex,and the vortex shedding frequency coincides with the experimental results ,meanwhile the higher precision is obtained on the calculation of cylinder surface pressure.