基于“各向异性”四面体网格聚合的复杂外形混合网格生成方法

摘要

A hybrid grid generation technique is presented in this paper for turbulence flow simulations over complex geometries.The hybrid grid generation technique is based on an 'agglomeration' method of anisotropic tetrahedrons.Firstly, the complex computational domain is covered by fully tetrahedral grids, in which anisotropic tetrahedrons are adopted to simulate the boundary layer, and isotropic tetrahedrons in the outer field.Then, the anisotropic tetrahedrons in the boundary layer are agglomerated to generate prismatic grid.The agglomeration method can improve the grid quality in boundary layer and reduce the grid quantity to enhance the numerical accuracy and efficiency of turbulence flow simulations.The hybrid grids over the standard DLR-F6 configuration from the second drag prediction workshop (DPW-Ⅱ), as well as a realistic fighter, are generated to validate present method.The numerical results agree very well with experiment data and those from other participants of DPW-Ⅱ.%复杂外形粘性流动的计算网格生成一直是阻碍CFD实际工程应用的瓶颈问题之一,虽然三棱柱/四面体混合网格的出现极大地缓解了这一问题,但是在飞行器几何外形非常复杂的情况下,在粘性边界层内生成高质量的贴体三棱柱网格仍然是非常困难的事情.本文从“各向异性”四面体网格的生成算法中得到启示,发展了一种基于“各向异性”四面体网格聚合的混合网格生成方法.通过对DLR-F6翼身组合体和F16战斗机外形的混合网格生成及数值模拟表明,该方法生成的混合网格具有网格质量好、自动化程度高等特点,对提高复杂外形飞行器关键气动参数的模拟精度具有重要意义.