23rd Congress of International Council of the Aeronautical Sciences, 8-13 September, 2002, Toronto, Canada
Paper ICAS 2002-3.7.2

EXPERIMENTAL INVESTIGATIONS ON THE ADAPTATION ACCURACY OF ADAPTIVE SLOTS IN WIND TUNNEL TEST SECTION WALLS

O. Meyer, S. Blume, W. Nitsche
Technical University of Berlin, Germany

Keywords: wind tunnel, adaptive test section, adaptive slots, adaptive walls

In many wind tunnel experiments the flow is affected by the presence of test section walls. These wall interferences can be minimized by correcting the measured model pressures or by influencing the model flow directly by means of ventilated or adaptive test section walls. The most successful technique of flexible, adaptive walls is still restricted to small research wind tunnels due to its mechanical complexity. However, a very promising alternative is the use of adaptive slots in test section walls. This paper presents the latest experimental results on the effectiveness of adaptive slots. The experiments were conducted under high subsonic flow conditions in the new slotted test section of the transonic wind tunnel at TU Berlin?s Aeronautical Institute (ILR). The results presented focus on detailed investigations of the slot flow itself and the 2D slot adaptation of a 2D model (CAST7 airfoil). The in-slot investigations show the cause for the reduced adaptation effectiveness of slotted test sections, depending on the slot and flow parameters. The derived adaptation corrections minimise the observed deviations. The fully adapted flows around the airfoil coincide in both test sections (2D-adaptive and slotted) with an experimental error of about 2%.

view full paper