モデル係数のscale dependenceを考慮したdynamic SGSモデルの適用 : 複雑地形上流れのLES (その3)

Abstract

A scale-dependent dynamic Smagorinsky (SDDS) model proposed by Porte-Agel et al. (2000) was introduced into the large-eddy simulation (LES) of a turbulent flow over a two-dimensional steep hill in order to improve the poor accuracy of the scale-invariant dynamic Smagorinsky (DS) model reported in our previous paper (2003). The accuracy was assessed by comparing the results with those from a wind tunnel experiment conducted by Ishihara et al. (1998, 2001), the standard Smagorinsky model, and the DS model. On the whole, the SDDS model provided accurate predictions and improved the poor accuracy of the DS model; however, the improvement was somewhat insufficient. Furthermore, the computational cost of the SDDS model was much higher than that of the other two models, mainly due to the cost of solving the polynomials for the scale-dependence parameter.