近壁面网格尺寸对湍流计算的影响

Effect of Near-Wall Grid Size on Turbulent Flow Solutions

采用不同的网格划分策略,利用FLUENT软件对长直圆管管内湍流进行数值计算.计算结果与半经验理论曲线的比较和分析表明,降低网格渐变率、提高径向网格数目以及调整壁面层网格的y+值均能够有效改善计算结果的精确性,而y+在其中起主要作用.针对同一网格划分策略,改变边界条件对计算结果精确性的影响相对较大,而改变模型引起的影响则相对较小,因此,不同边界条件应采取相应的网格划分策略尤其是选择合适的近壁面网格尺寸.

Adopting various meshing strategies, numerical calculation of internal turbulent flow in long straight circular pipes is proceeded by the FLUENT software. Comparison between calculated results and curves of semi-empirlcal expressions shows that the numerical solution is effected by mesh size, ratio and the y ^＋ value of the near-wall grid that plays a crucial role in the effect. At the same model and identical meshing strategy, different boundary condition leads to different accuracy of the result. Otherwise, different model will not cause significant difference in accuracy at the same boundary condition and meshing strategy. Thus, suitable meshing strategy especially the near-wall grid size should be selected to adapt to different boundary condition.