Wind Tunnel and Flight Tests with Active Flow Control on a S10 Glider Configuration

Abstract

This paper presents active flow control results using periodic excitation on a wing section with a plain flap of a Stemme S10 glider configuration for wind tunnel and flight tests. A periodic pulsating jet, coupled in from the suction side of the flap near the separation area, was used to delay flow separation for both cases. The wind tunnel experiments were carried out in a closed loop wind tunnel at a Reynolds number of Re c = 1.75·106. In addition to measurements with a six-component balance, pressure measurements in the middle section of the model were carried out. An improvement of up to 30% in the lift-to-drag ratio can be observed by controlling the flow separation on the flap. The flight tests were carried out with an S10 motor glider in cooperation with Stemme AG. By using the excitation parameters identified in wind tunnel tests, separation was successfully delayed by active flow control in the flight tests. In addition to the flow visualization using surface tufts, pressure measurements on the flap and the main wing were carried out.