Unsteady aerodynamics of slat cove flow in a high-lift device configuration

The unsteady flow around the leading edge slat of a three-element high lift aerofoil configuration has been experimentally investigated using Particle Image Velocimetry (PIV) and Laser Doppler Anenometry (LDA). The two-dimensional UK National High Lift Programme model was tested in the University of Southampton 3.5m × 2.5m R. J. Mitchell and 2.1m × 1.7m wind tunnels. Instantaneous PIV results and LDA turbulence statistics reveal the unsteady nature of the slat cove flow, and its cavity-like characteristics. The presence of large, spanwise rollers within the shear layer emanating from the slat cove lip has been shown. The slat trailing edge wake resembles a mixing layer with no vortex pairing in the region up to one slat chord downstream. Increasing angle of attack has the effect of stabilising the flow around the slat and significantly reducing the turbulent kinetic energy and normal Reynolds stress within the cove.