This book aims to use latest numerical techniques of computational fluid dynamics, CFD, to estimate a more accurate wind pressure for building clusters with different heights and arrangements. With these new numerical simulations, design for wind loads become more rational and less dependent on empirical rules that may lead to serious errors when applied beyond their range. These techniques, especially virtual wind tunnel, require considerably low cost and time compared with those required for the conventional wind tunnel. In addition, they work directly with design prototype instead of a scaled-down model in the conventional wind tunnel. Two separated buildings have been simulated with the help of Building Information Modeling, BIM, which allows analysis of two building at the same time. During this simulation, the interference effects of two buildings have been examined due to wind load excitation.