高次精度差分法による二次元円柱周り流れの直接数値計算 : 流出境界条件の検討

概要

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A direct numerical simulation (DNS) of flow around a two-dimensional circular cylinder by the higher-order finite difference scheme (FDS) is conducted. Inflow and outflow boundary conditions constructed and successfully tested originally on a spatially developing mixing layer are applied to the above mentioned flow with R_e=226. Comparisons of the general flowfield and the statistics with those obtained in an extended computational domain arc made. In addition, the appropriateness of the outflow boundary condition imposing the zero gradient of the velocity and pressure is investigated. From these studies, the following conclusions are obtained. (1) For the newly proposed outflow boundary condition, the velocity and pressure fields are highly correlated to the results obtained in the extended computational domain. The correlation coefficient of the pressure with that obtained in the extended computational domain is higher than 0.999. (2) For the conventional zero gradient condition, a significant discrepancy from results obtained in the extended domain is observed for both velocity and pressure fields, and the correlation coefficient of the pressure is as low as 0.966. (3) The conventional zero gradient condition overestimates the drag coefficient.
一般社団法人日本機械学会の論文
1996-08-25