用非结构直角网格和欧拉方程计算运载火箭绕流

采用八叉树结构，物面附近用投影法，生成运载火箭绕流计算的非结构直角网格。并将Jameson的有限体积法推广用于这种网格的欧拉方程计算。算例表明，网格生成的时机化费很少，质量好；欧拉方程解算的收敛质量也好。

Computation of the flow past launch vehicle using unstructured Cartesian grid and Euler equations

Unstructured Cartesian grid for the flow past a launch vehicle was generated based on Octree data structure.The method is to subdivide recursively the root Cartesian cells as the cell near the body surface.The projection method was applied near the body surface to make the grid bodyfitted.The feature of the method is that the body geometry can be provided by the surface triangulation of individural components rather than that of the whole configuration.The resulating geometry is the union of them.This approach greatly simplifies the work of the computation prepared by the user.Jameson's finite volume method is then extended to such grid to solve the Euler equations.The sample computation shows the low cost of the CPU time for grid generation,and the good convergence level reached for flow computation due to the good quality of the computational grid.