Computational Fluid Dynamics (CFD) is the analysis of systems involving fluid flow, heat transfer, chemical reactions by using computer based simulation. CFD is used for a wide range of industrial and academic research areas, such as: – Airplanes and vehicles aerodynamics. – Internal combustion engines and turbomachinery. – External and internal environment of buildings: wind loading, ventilation and fire dynamic simulation. – Biomedical and pharmaceutical applications. – Heat exchangers design. – Mixers and chemical reactors. CFD uses generally the finite volume method where the computational domain is divided into a number of smaller sub-domains called elements or cells which constitute the mesh. The continuity and momentum equations (Navier-Stokes equations) are hence solved in each cell using appropriate numerical methods and schemes. The flow can be modeled either laminar or turbulent. When the flow is turbulent, a turbulence model is used depending on the flow nature. WTA uses the latest software for CFD simulation, and has already done projects requiring Smoke Management, Ventilation, Thermal Comfort and Wind Tunnel Test.