双対空間を用いたHybrid型上流化有限要素法 : 第4報, 高Rayleigh数自然対流間題によるスキームの検証

抄録

In the present paper, unsteady natural convection flows of air in a square cavity with differentially heated walls are investigated numerically using the hybrid-GSMAC (generalized and simplified marker and cell) finite-element method. A direct-numerical simulation of two-dimensional turbulence is shown in the present paper without introducing any random forces. The present result at Rα=1.0×10⁸ is compared with the other numerical results. The present result of calculation is in good agreement with that of the others This study allows us to say that the hybrid-GSMAC method suggested by Tanahashi is clarified. In addition, selected frames from an animation generated from the computational results at Rα=1.0×10⁹ show very clearly the formation of large-scale eddies via the following sequence : initial instability, proceeding through transition, and eventually the statistical steady state. Using this method, it is possible to investigate natural convection and heat transfer phenomena at high Rayleigh numbers up to 10¹0.