Aerodynamic Control of a Rectangular Wing Using Gurney Flaps and Synthetic Jets

Abstract

An experimental investigation was performed on a rectangular wing section at low angles of attack to determine the aerodynamic flow control eectiveness of pairing a near-trailing-edge Gurney flap with an array of synthetic jet actuators. In this investigation, a Gurney flap was placed a small distance upstream of the synthetic jet actuator orifice with the goal of using the synthetic jet actuators to augment the eects of the Gurney flap. The main advantage of the Gurney flap was a lift increase that was accompanied by a separated region downstream of the flap which the synthetic actuators were able to manipulate for additional lift increments. Sectional lift and quarter-chord pitching moment data were acquired at Rec = 1.57 ◊ 10 5 and angles of attack ranging from = 0 - 12 for dierent configurations of the Gurney flap and synthetic jet array. For configurations where significant aerodynamic control was observed, the flow physics in the vicinity of the flap and actuators were investigated with ensemble-averaged PIV measurements. These measurements showed that the control scheme could either augment or reduce the lift on the wing section depending on the location of the synthetic jet actuators. When the synthetic jets were placed on the pressure surface, the control scheme had a lift increase on the order of 10% and a corresponding decrease in the pitching moment for the range of angles of attack investigated. When the synthetic jets were placed on the suction surface, the control scheme had the opposite eect with percent decreases in lift of 10% or greater. These changes in the lift and pitching moment were the result of a change in the circulation around the wing section by a modification of the trailing edge flow in the wake of the Gurney flap. Thus it was shown that the synthetic jet actuators were able to manipulate the wake of the Gurney flap and augment the eects of the Gurney flap.