直交格子法における物体境界近傍の直接离散化法.PDF

605 日本機械学会論文集（B編） 原著論文No.2012-JBR-0631 79巻 800号 （2013-4） 直交格子法における物体境界近傍の直接離散化法＊ （速度場と圧力場の整合性を考慮した高精度化） *1 *2 *3 *1 *4 佐藤 範和 ，梶島 岳夫 ，竹内 伸太郎 ，稲垣 昌英 ，堀之内 成明 A Direct Discretization Approach near Wall Boundaries for a Cartesian Grid Method (Consideration of Consistency between Velocity and Pressure Fields) Norikazu SATO*1, Takeo KAJISHIMA, Shintaro TAKEUCHI, Masahide INAGAKI and Nariaki HORINOUCHI *1 Toyota Central RD Labs., Inc., 41-1, Yokomichi, Nagakute, Aichi, 480-1192, Japan A new discretization scheme for a Cartesian grid method is proposed. The Navier-Stokes equation is discretized directly even in the boundary cells in order to ensure the momentum conservation. Furthermore, the Navier-Stokes equation and the pressure Poisson equation in the boundary cells are constructed with the properly interpolated flux and pressure gradient. This treatment guarantees the consistency between the velocity and pressure fields in the boundary cells. The validity of the present method is assessed in some fundamental flows. It is found that the present method significantly improves the accuracy orders for the wall shear stress as well as the velocity compared to the voxel method and the conventional direct forcing immersed boundary methods. The results by the present method are also found to be less dependent on the Courant number due to the consideration of the consistency between the velocity and pressure fields in the vicinity of the boundary. The method is also applied to a large eddy simulation of a flow past a circular cylind