Re-No. Scaling Effects on the EUROLIFT High Lift Configurations

Abstract

Within the European projects EUROLIFT (I) and II extensive experimental and numerical investigations on the aerodynamics of high lift configurations have been carried out. The studies are conducted using the KH3Y wind tunnel model (DLR F11), which is representative for a wide-body commercial aircraft. A step by step complexity increase up to a complete high lift configuration including pylon, nacelle, and nacelle strake is carried out to identify and separate the lift and drag behavior for the components of the high lift system and their Reynolds-number dependency. The wind tunnel data have been gathered in the European Transonic Windtunnel ETW in Cologne in three different test campaigns. To include the detailed analyses of the stall behavior for the different configurations for a complex 3-dimensional tapered high lift wing with nacelles extends the scope of a single paper. Therefore the focus of the present contribution is laid on the detailed analysis of Reynolds-number scaling effects with respect to lift curves and drag polars. The combined variation of the dynamic pressure and the total temperature in the ETW allows to cover a Reynolds-number range from Re ~ 1,5 x 10 6 up to deep cryogenic conditions with Re ~ 25 x 10 6 . The final comparison of the four configurations reveals, that the sequence of maximum lift values is maintained for the lowest and highest Reynolds-number, while the deltas between the configurations differ. The strongest increase in maximum lift is observed up to Re ~ 5 x 10 6 . In the intermediate range 5 x 10 6 <Re < 15 x 10 6 a highly non-linear behavior of the maximum lift values is observed, which requires further investigations.