Experimental Analysis of Separation and Transition Phenomena for the DLR-F11 High Lift Configuration

Kurzfassung

The paper describes an evaluation of the experimental evidence for the DLR-F11 high lift configuration as used within the context of the 2nd phase of the AIAA High Lift Prediction Workshop. The configuration is representative for a wide-body commercial aircraft. For the present purpose a wing/body combination with a continuous slat and flap system in landing setting is considered. The experimental data have been gathered in 2001 within the European project EUROLIFT. The present contribution focuses on transition and separation effects for a low Reynolds numbers test (Rec = 1.35 x 106) under atmospheric test conditions in the Low Speed Wind Tunnel of Airbus Bremen, B-LSWT, in Germany. The considered data are complementary to a body of data that has already been provided for use in the AIAA High Lift Prediction Workshop 2. As no related publications are available for the transition data under consideration, an attempt has been made to compile and cross-compare the experimental evidence in order to get a conclusive picture of the related main aerodynamic phenomena. The discussion of the experimental results starts with the presentation of an evaluation of hotfilm data supported by infrared images at the midboard section of the wing for various angles of attack up to and beyond maximum lift. In a second step, transition and separation phenomena at the three spanwise observation areas on the wing are analyzed to assess spanwise trends for two selected angles of attack. For this purpose, also oil flow pictures are used to support the evaluation. Transitional effects are present an all three elements of the high lift wing, most pronounced for the angles of attack below max.