三维复杂无粘流场的自适应八叉树结构直角网格算法模拟

NUMERICAL SIMULATION FOR 3-D COMPLEX INVISCID FLOW FIELD WITH ADAPTIVE OCTREE CARTESIAN GRIDS

运用自适应八叉树结构直角网格对三维复杂流场进行了划分 ,并采用点面判别法进行外法向量的判断 ,使与之关联的与物面相交网格的体积计算更为简便准确。在此基础上 ,采用以中心差分为基础的 Jameson的有限体积法进行 Euler方程求解 ,在通量计算过程中 ,采用以面为基础的算法 ,减少了计算工作量。对多个外挂、翼身组合体及全机等复杂外形绕流流场进行了模拟 。

An adaptive octree Cartesian mesh approach is presented to generate grids for computation of the complex flow field. In this grid method, based on the original Cartesian mesh approach, a surface judging relation is presented to calculate the volume of 3D cut cell since it is difficult to calculate the outward normal. Results show that this method can indeed compute the volume precisely and greatly improve accuracy of simulation of the flow field. Additionally, the new organized data structure, based on the octree method, can decrease the volume of the time to generate the grid. Furthermore, to predict the flow field, Jameson's finite volume method with the central difference scheme is used to develop an Euler solver. In this solver, since an algorithm, looping with the faces, is used in the computation of the numerical flux, the efficiency of the computation is well improved. Numerical simulations of multi\|store, wing\|body combination and whole aircraft complex configurations, good agreement with the experimental data are obtained. It verifies the validity of the method presented in this paper.