Depending on the field of application, different flow phenomena occur. With small Reynolds numbers, laminar separation bubbles can form, which may lead to a noticeable increase in the drag coefficient, but are difficult to calculate. As the Mach number increases, compressibility effects increasingly influence the flow around the profile. If a critical Mach number is exceeded, shock waves can occur which have a dominant influence on the drag. In addition, complex shock-boundary-layer interactions occur.
The aerodynamic properties of an airfoil and thus the performance of an aircraft are decisively determined by the design of the profile sections. The design and analysis of profiles therefore plays an important role in aircraft aerodynamics. Usually, tailor-made profiles are developed for each application, for which reliable calculation methods are required.
The Institute has many years of experience, particularly in the design and optimisation of subsonic profiles, whereby the trailing edge noise is taken into account for profiles for wind energy applications. For the analysis of the profiles we use commercially available as well as self-developed calculation tools. Depending on the application, different methods (potential boundary layer method, Euler boundary layer method and Navier-Stokes method) are used. A verification of the theoretical results is possible in the subsonic range in the Laminar Wind Tunnel of the institute. The extensive experimental investigations carried out there facilitates further development of the profile design and analysis methods.