Computational Fluid Dynamics (CFD) is a numerical technique for solving and analysing problems that involve fluid flows. Fluid Structure Interaction (FSI) is an advanced simulation method that analyses interaction of deformable structures with an internal or surrounding fluid flow using results of CFD analysis. These have recently been utilised in the building industry and in particular in projects with irregular shapes where simplified methods outlined in the standards are not applicable. CFD and FSI analysis can provide all the information that is normally obtained from wind tunnel tests.