Abstract
The numerical simulation code with a finite difference method for unsteady three-dimensional wind flows was developed in a Cartesian grid system. The immersed boundary method, which enables us to represent the complex geometry in the Cartesian grid system, was used. In addition, the fluid characteristics of complex turbulent flows were predicted with a large eddy simulation, which is based on a mixed time-scale SGS model. The present code was applied to the prediction of flow fields over a steep hill, and it was confirmed that the present results agreed well with those obtained by BFC code, indicating that the present code is suitable to predict the fluid characteristics in the boundary layer over a steep hill.
