The performance of structured and unstructured grids on wind simulations around a high-rise building

In this study, computational fluid dynamics has been applied to analyze the performance of both structured and unstructured meshes when used in steady-state simulations of wind in an urban area. This case specifically examines the wind environment around a single high-rise building with the geometry of 1: 1: 2 (length, width, height) within the atmospheric boundary layer.The Reynolds-averaged Navier-Stokes simulations were conducted using OpenFOAM, with grids generated with blockMesh, snappyHexMesh, and Pointwise. A set of coarse meshes and a set of fine meshes were used for comparison.Minor differences in the flow pattern were observed depending on the mesh type used, including the reattachment lengths, the drag coefficients, the velocity profiles, and the positioning of the vortex leeward of the high-rise building. However, the main flow features were the same, indicating that for simulations where overall flow features are of importance there is high flexibility in choice of meshing technique