Effect of grid size on building wind according to a computation fluid dynamics simulation

Skyscrapers negatively impact the environment by creating gusty winds, known as building winds, which are the result of descending turbulences caused by the blockage of upper air by tall buildings. Usually, a building wind impact assessment (BWIA) is carried out using a wind tunnel test or computation fluid dynamics (CFD) simulation methods. The application of wind tunnel test is limited by the high costs of the models. Thus, CFD simulations are now the preferred approach to save time and expense as a result of advancements in computer technology, however, differing grid cell sizes greatly impact simulation results. Therefore, it is important to select appropriate cell sizes. CFD simulations based on different grid sizes were tested and compared in this study. The study site is located in the Dogok-dong at Gangnam-ku in Seoul, Korea. The study results revealed significant errors when using coarse grid sizes due to incorrect representations of building shape.