嵌套重叠网格的构造策略及其隐式切割

高质量网格的设计与生成是复杂流动CFD精确计算最主要的决定性因素之一．本文通过采用新颖的多层嵌套重叠网格策略、可靠的重叠网格切割准则、快速的多级网格切割方法和高效的隐式切割技术，发展了一种多层多块隐式嵌套重叠网格技术以及相应的多级多重网格流动计算方法．在生成嵌套重叠网格时，只需要初始网格和边界条件，而无需人工干预，实现了嵌套重叠网格的自动切割．对某级网格进行多重网格流动计算时，仅考虑该级网格的嵌套重叠切割处理，而忽略低级粗网格的网格切割影响，有效提高了流动的计算效率．两个典型的复杂流动算例的计算结果与实验值吻合良好，证明了本文方法的可靠性．

An automated Chimera method based on a hierarchical overset grid strategy and the implicit hole cutting technique

An automated multi-layer multi-block Chimera overset grid algorithm is presented for accurate simulation of viscous flows around complex configurations. The algorithm is based on the implicit hole cutting （IHC） method introduced by Lee and Baeder, which is enhanced with a novel hierarchical overset grid strategy and a feasible grid quality criterion to eliminate its shortcomings. The enhanced method only needs the grid data and boundary conditions provided by the user. And no user-defined grid ranking or helper geometries have to be defined. With the enhanced algorithm, several classical aerodynamic test cases are performed with a modified multi-grid and mesh-sequencing to achieve convergence acceleration. Moreover, all the computed aerodynamic forces are agreed excellently with the experimental data. It demonstrates the accuracy, efficiency and practicality of the enhanced algorithm.