二维格子Boltzmann方法圆柱绕流湍流模拟

Two-dimensional simulation of flow around cylinder with multiple-relaxation-time lattice Boltzmann method

采用多松弛格子Boltzmann方法的大涡模拟技术对二维圆柱绕流问题进行了数值模拟.运用二阶插值反弹格式处理圆柱边界,同时结合Wall-Adapting Local Eddy-viscosity模型(WALE)对壁面附近湍流粘性进行修正,测算了其升、阻力系数和涡脱落频率.结果显示:在雷诺数小于300时,升、阻力系数以及涡脱落频率均跟实验值吻合较好;对于较高Re数问题,其三维效应不能忽略,模拟结果跟实验值有所偏差,但通过引入WALE模型进行壁面修正,该方法较其他二维方法在估算阻力系数上精度有明显提高.

Based on the multiple-relaxation-time lattice Boltzmann method,large eddy simulation is adopted to explore the flow around a two-dimensional cylinder.The interpolation bounce-back boundary condition is used to treat the boundary of the cylinder,and wall-adapting local eddy-viscosity（WALE） model is used to adjust the turbulent viscosity near the wall.The lift coefficient,drag coefficient and vortex shedding frequency are calculated.When the Reynolds number is lower than 300,the vortex shedding frequency,drag coefficient and lift coefficient coincide with the experimental values.The results also show,for higher Reynolds number flow,3D eddy＇s structures play important roles during the flow.However,the correction of wall turbulence viscosity improves the accuracy during the two-dimensional simulation.