Typically, the flow problems are divided into two groups: internal and external. Fundamentally, the internal flow analysis is defined as the analysis of any flow passing through a closed object. The external flow analysis, on the other hand, focuses on the effects generated by the flow passing over a design or system. These flow problems are solved by ANSYS-CFD software with the best approach depending on the flow regime (i.e., laminar or turbulent) in the most accurate and fastest manner. Majority of the flow problems in the industry have turbulent flow regimes. In cases where the regime is turbulent, the solution is attained either by creating very thin boundary layers on the surfaces touched by the flow, or by choosing the appropriate wall functions. The internal and external flow analyses have a vast area of industrial use, including but not limited to the industries of aviation, defense, automotive, constructions, shipbuilding, nuclear, and machinery. The internal flow analysis is mostly used for the systems of manifold, exhaust, cooling, and pumping, whereas the external flow analysis is more common in the designs of wind turbines, aircrafts, and cars.
