Manipulation of Attachment Line Transition by Geometry Modification at the Slat of a Multi-element Airfoil.

This study shows the application of the criterion of Pfenninger for the prediction of the influence of geometric variations at the slat of a multi-element airfoil on the occurrence of attachment line transition (ALT). Additionally the use of criteria for the prediction of relaminarization based on the results of 2D RANS computations is examined. Flow calculations are performed for a representative wing section of a three-dimensional swept and tapered high-lift wing for which the occurrence of ALT is assumed at higher Reynolds numbers. Systematic geometry variations are performed to investigate the influence on the predicted onset of ALT and the influence on aerodynamic characteristics in order to identify possibilities for the design of a slat with delayed ALT onset. From this the most sensitive parameters for ALT transition and aerodynamic performance have been identified. [ABSTRACT FROM AUTHOR]