Investigation of the boundary layer of a delta wing in transonic flow by means of 3 component Laser Doppler Anemometry

Abstract

In the development of numerical codes for the prediction of vortex flow there is a strong need to obtain reliable flow field data which is suited to validate turbulence models used in time averaged Navier-Stokes calculations. Especially three dimensional boundary layer velocity data is of interest. Therefore the boundary layer of a vortex generated by delta wing model with 65 degree sweep has been investigated by means of a 3D Laser Doppler Anemometer (3D LDA). The experiments were carried out in the Transonic wind tunnel (TWG) in Göttingen. The model was tested with an angle of attack of 15 degree. The wind tunnel was operated at a fixed Mach number of 0.85. This corresponds to a Reynolds number based on the model base chord length of 6.24 x 1000 000. The measurements were performed using a three component Laser Doppler Anemometer system designed by DLR Göttingen for the application in transonic flow. The LDA system was operated in a back scatter optical arrangement. Velocity data as well as turbulent quantitities have been successfully acquired close to the surface of the model. Additionally the vertical motion of the model has been monitored