用格子Boltzmann方法模拟方柱绕流

Simulation of flow around square cylinders by lattice Boltzmann method

基于格子Boltzmann方法的原理和对边界条件处理的便捷性,分别对单方柱和并列双方柱绕流进行了研究。对于单方柱绕流,分别研究了不同雷诺数和阻塞比对它的影响,给出了不同雷诺数下单方柱绕流的流线图和涡量图,以及平均阻力系数和最大升力系数随雷诺数的变化曲线,得到单方柱产生卡门涡街的临界雷诺数,也给出了不同阻塞比下单方柱绕流的涡量图,以及不同阻塞比对平均阻力系数和最大升力系数所产生的影响。对于并列双方柱绕流,研究了不同间距比对它的影响,给出了不同间距比下的并列双方柱绕流的流线图和涡量图,得到了流动从偏流型向对称型转换的临界间距比以及使得两个方柱后的涡流互相影响最为明显的间距比。

Based on the lattice Boltzmann method and the convenience of the boundary condition processing,the flow past a single square cylinder and the parallel square cylinder were studied respectively.For the single square cylinder flow,the effects of different Rayleigh numbers and blocking ratios on it are studied separately,the streamline diagram and vorticity diagram of the flow around a single square cylinder under different Rayleigh numbers,and the variation curve of the average drag coefficient and the maximum lift coefficient with the Rayleigh number are given.The critical Rayleigh number of the Karman vortex street generated by the single square cylinder is obtained.The vorticity diagrams of the flow around a single square cylinder with different blocking ratios and the effects of different blocking ratios on the average drag coefficient and the maximum lift coefficient are also given.For the parallel flow around the two square cylin⁃der,the influence of different spacing ratios on the flow is studied.The flow diagram and vorticity diagram of the flow around the two square cylinder at different spacing ratios are given,and the flow from the bias flow to the symmetrical conversion is obtained.The eddy currents behind the two square cylinder affect each other's most obvious spacing ratio.