有翼大気圏再突入機の空力特性予測に適したプリズム格子生成法

Abstract

This study proposes a computational grid generation method to generate prismatic grids suitable for shock adaptation around a winged re-entry vehicle. The grid generation method proposed here is based on an existing method (Takanashi, S., Computers & Fluids, 19 (1991), pp. 393--399), which uses the theory of electric force lines to determine the computational grid lines. In order to control the distortion of the prismatic grids, the proposed method introduces three modifications to the existing method: 1) the grid generation process is divided into two stages, 2) the height of the prism layers is adjusted by considering the curvature of geometries, and 3) the cell width is optimized using the spring analogy. Both the proposed and existing methods are applied to generation of computational grids for a winged re-entry vehicle, HYFLEX. It is found that the existing method gives a computational grid containing cells not suitable for flow computations. On the other hand, the proposed method successfully gives a computational grid with which the flow computation is stably performed. By applying an adaptive refinement of prismatic layers to the detached shock wave, a smooth flow field is obtained behind the sharply resolved shock wave.