Building-Cube Methodによる圧縮性Eulerソルバーの構築と航空機翼のフラッタ解析への応用

摘要

近年，航空機の空力設計において数値流体力学(CFD)を用いた空力最適化が盛んに行われている.例えば，三菱航空機のMRJ(Mitsubishi Regional Jet)では本研究室で開発された非構造格子CFDソルバー(TAS-code)を用い，ウイングレット等の空力最適化が行われた.%In recent years, the aerodynamic analysis using computational fluid dynamics (CFD) has been widely used in the actual aircraft design. Especially, unstructured mesh method is widely used now, because it can treat complex objects. However, there are several difficulties in the current CFD, for example difficulty in the large scale parallel computation, in the mesh generation applying to the much complex objects, in the deformation of the volume mesh, and so on. To overcome these issues, the Building-Cube Method (BCM) based on the equi-spaced Cartesian mesh has been proposed. As is widely recognized, the biggest issue to use Cartesian mesh approach is the treatment of wall boundaries. In this study, Immersed Boundary Method (IBM) with ghost cell/image point approach is implemented. Virtual flux concept is also implemented to compute thin components like trailing edge of a wing. The Cartesian mesh solver has advantages in treating the moving boundary problems, because of the easy mesh generations. Therefore, the nonlinear flutter simulations are also carried out by direct coupling of the compressible Building-Cube Method and the structural equations.