Abstract
In order to develop an overall efficient and accurate model of simulating an unsteady three-dimensional airflow over complex terrain with characteristic length scales of the order of kilometers, we have been examining the large-eddy simulation (LES) technique using a finite-difference method (FDM). These LES codes are referred to as the RIAM-COMPACT (Research Institute for Applied Mechanics, Kyushu University, Computational Prediction of Airflow over Complex Terrain), and are based on two grid systems and corresponding variable arrangement : one is an orthogonal staggered grid; the other is a generalized curvilinear collocated grid. In this paper, using the RIAM-COMPACT with a generalized curvilinear collocated grid, we have performed the calculations of stably stratified airflows over an isolated steep hill. A strong wind area caused by the lee wave was clearly seen near the first trough behind the hill. Next, we made the calculations of stably stratified airflows over Mt. Miyake. Particularly, the behavior of the passive particles from the top of Mt. Miyake was investigated.
