2016 Volume 51 Issue 3 Pages 161-173
A number of automatic grid generators for numerical simulations has been developed in recent years. These utilities and CFD code using an unstructured grid enabled us to calculate the flow and dispersion over complex terrains with buildings. However, no reports are available regarding the large eddy simulations (LES) of contaminant dispersion using these utilities. This study was made to clarify the applicability of these grids to the simulation of flow and contaminant dispersion over a two-dimensional hill compared to the legacy orthogonal grids. We found that the characteristics of the separated flow were affected by the grid types near the terrain. Consequently, the contaminant dispersion was also strongly affected by the grid types due to the differences in the separated flow. We concluded that the grids near terrains should be parallel to the flow direction for the accurate predictions of contaminant dispersion.
