Wind Tunnel Experiments with Active Flow Control for an Outer Wing Model

Abstract

This contribution discusses the implementation of fluidic slit-actuators as well as fluidic vortex generators on a three dimensional model of the outer wing of a long-range transport aircraft at take-off, by low speed wind tunnel experiments in the large test facility of DNW-NWB. The leading-edge high-lift unprotected wing extension, including a wingtip device, designed for high performance at cruise flight, is subject to local flow separation at high angles of attack and low speed flight conditions. Active flow control (AFC) applied at the outer wing can prevent the formation of large turbulent flow separation and increase the aircraft lift to drag ratio (L/D), decrease the drag (D), and increase the angle of attack (AoA) for maximum lift (CLmax). The recently performed experiments show the improvement in the aerodynamic coefficients by the local AFC applications. The drag coefficient decreases of up to 40% at fixed large AoA, while the maximum AoA is proved to increase in the order of 2°. The results suggest a successful implementation on a transport aircraft and with an acceptable blowing momentum coefficient.