Optical Skin Friction Measurements in Short-duration Facilities (Invited)

Abstract

The utilization of image acquisition, image processing and skin friction computations has been developed to support optical skin friction measurements in short-duration facilities. Verification of the oil-film-interferometry technique with analytical tests showed the advantages and handicaps for the application of skin friction measurements in 3D gradient flows. The abilities of this technique with its application in the supersonic Ludwieg Tube Facility at DLR are demonstrated in intensified investigations of two standard CFD validation cases for shock wave / turbulent boundary layer interactions (SWBLI): 2D weak-to-strong oblique SWBLI on a flat plate as well as 3D swept SWBLI in the vicinity of a single fin configuration with a deflection angle of 23 degree at Mach number 5. The results establish a data base of two data sets for CFD validation, consisting of the boundary layer flow-field, surface pressure and heat flux data as well as flow visualizations.