External Aerodynamics

In fluid mechanics, an external flow is such a flow that boundary layers develop freely, without constraints imposed by adjacent surfaces. Accordingly, there will always exist a region of the flow outside the boundary layer in which velocity, temperature, and/or concentration gradients are negligible.It can be defined as the flow of a fluid around a body that is completely submerged in it.

External aerodynamic flows can be frequently encountered in the industry with applications including the fluid motion over a flat plate (inclined or parallel to the free stream velocity), the flow over curved surfaces such as a sphere, cylinder, airfoil, or turbine blade,air flowing around an airplane, ground vehicles or water flowing around submarines.

 

 

In fluid mechanics, the boundary layer is the thin layer of fluid in the immediate vicinity of a solid boundary where the viscosity effects are of great importance. The flow over a flat plate and the development of its boundary layer has been first studied by Blasius in 1908 thus often associating this test case with the name "Blasius solution" (Read more).

 The flow behind a circular cylinder has always been a major research and validation test case both for its simple geometry and for its great practical importance in engineering applications. This test case focuses on the steady laminar flow at low Reynolds numbers as well as on the unsteady vortex shedding that appears with increasing Reynolds number (also called Von Karman Vortex Street) (Read more).
  This test case aims to validate the realizable k-Epsilon turbulence model by studying the recirculation zone that forms when a turbulent flow pases over a blunt flat plate (Read more).