Control of Separation on the Flap of a Three-Element High-Lift Configuration

This paper describes a joint experimental and numerical investigation of the control of the flow over the flap of a three-element high-lift configuration by means of periodic excitation. At Reynolds numbers between 0.3 × 10 and 1 × 10 the flow is influenced by periodic blowing or periodic blowing/suction through slots near the flap leading edge. The delay of flow separation by periodic vertical excitation could be identified in the experiments as well as numerical simulations based on the Unsteady Reynolds-averaged Navier-Stokes equations (URANS). As a result, the mean aerodynamic lift of this practically relevant wing configuration could be significantly enhanced. By investigating different excitation frequencies and intensities optimum control parameters could be found. The behaviour of the aerodynamic forces with varying flap deflection angle are measured on a finite swept wing. Scientific visualisation of the numerical simulations of an infinite swept wing allows a detailed analysis of the structures in this complex flow field and the effect of flow control on these.