LIFT AND DRAG COEFFICIENTS BEHAVIOUR AT LOW REYNOLDS NUMBER IN AN AIRFOIL WITH GURNEY FLAP SUBMITTED TO A TURBULENT FLOW. PART 1

Boundary layer wind tunnel experiments have been conducted in order to investigate the influence of a Gurney flap upon the aerodynamic behaviour of an HQ 17 airfoil. The airfoils, with and without the Gurney flap, were submitted to two different turbulent flows with the same mean wind velocity but with different turbulence structures. Lift and drag coefificients were calculated in both cases, then plotted and contrasted with low velocity laminar wind tunnel data of the HQ17 with and without miniflaps Gurney, obtained from Bechert et al. (2000) at the DLR, Technical University of Berlin, Germany. The results show that the Gurney flap acts enhancing the lift coefficient of the airfoil, and that its performance is almost independent of the scales of the incoming turbulence. The tests were performed at a turbulence intensity of 1.8% and 3.5% and at a Reynolds number of 3x10(-5).