基于格子玻尔兹曼方法(lattice Boltzmann method,LBM)对湍流模拟进行研究,提出了一种雷诺平均(Reynolds-averaged Navier-Stokes,RANS)模拟和大涡模拟(large eddy simulation,LES)结合的混合湍流模拟(RANS/LES-LBM)方法.该方法利用RANS中的混合长度湍流模型,修正了传统Smargorinsky模型在近壁面处误差较大的问题.基于该方法,还自主开发了一套混合湍流模型的LBM并行程序,对圆柱绕流、NACA0012翼型绕流、30P30N三段翼型绕流问题进行了数值计算.结果表明,RANS/LES-LBM方法改进了近壁面处的误差,具有更高的计算精度,同时对复杂的高雷诺数流动也具有良好的稳定性.LBM并行程序使用OpenMP编程模式进行了并行计算.分析结果表明,该程序具有良好的加速比、可扩展性等并行性能.同时,对LBM多层网格进行了研究,为今后开展复杂几何流动问题数值模拟奠定了基础.
A hybrid turbulence simulation method combining Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES) was proposed based on the lattice Boltzmann method (LBM). RANS/LES-LBM method used a mixed-length RANS turbulence model to solve the problem of large errors in the conventional Smagorinsky model near the wall. Based on the method, a set of LBM parallel programs was independently developed for the hybrid turbulence model. Cylindrical, NACA0012 airfoil flow, and 30P30N three-segment airfoil flow problems were numerically calculated. Calculation results showed that RANS/LES-LBM method improved the error near the wall, had higher calculation accuracy, and exhibited good stability for complex high-Reynolds number flows. LBM paralled program used the OpenMP programming mode for parallel computing and showed good speed-up ratio, scalability, and other parallel performances. LBM multilayer meshes were also studied, which laid the foundation for the numerical simulation of complex geometric flow problems in the future.
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