Wall adaptation and determination of residual wall interferences for a 2D and a 3D model in the transonic wind tunnel TWG of DLR

The transonic wind tunnel TWG of DLR Gottingen has been modernized with respect to an improved flow quality as well as to the logistics of exchangeable test sections, operational reliability and productivity. It is presently equipped with a Laval nozzle (supersonic), a perforated test section (transonic) and a two-dimensional adaptive (subsonic) test section. The latter can perform 2D adaptive tests on wing profiles using the Cauchy integral formula for wall adaptation, as well as 2D wall adaptation for 3D models utilizing the Wedemeyer/Lamarche (VKI) procedure. For both cases the wall adaptation was successful. The 3D force results compare quite well nominally interference-free results and to results from another adaptive test section. The pressure distribution from the wing profile tests agree quite well with theoretical results. For the 3D model, residual wall interferences were determined. It was found that the wall interferences had been reduced to nearly zero on the centreline of the test section by wall adaptation. Spanwise averages of the residual wall interferences have been used for further corrections