24-10-2012, 01:28 PM
PIV Measurements on a Blowing Flap
ABSTRACT
PIV measurements of the flow in the region of a flap side edge are presented for several blowing flap configurations. The
test model is a NACA 63(sub 2)-215 Hicks Mod-B main-element airfoil with a half-span Fowler flap. Air is blown from small
slots located along the flap side edge on either the top, bottom or side surfaces. The test set up is described and flow
measurements for a baseline and three blowing flap configurations are presented. The effects that the flap tip jets have on the
structure of the flap side edge flow are discussed for each of the flap configurations tested. The results indicate that blowing
air from a slot located along the top surface of the flap greatly weakened the top vortex system and pushed it further off the
top surface. Blowing from the bottom flap surface kept the strong side vortex further outboard while blowing from the side
surface only strengthened the vortex system or accelerated the merging of the side vortex to the flap top surface. It is concluded
that blowing from the top or bottom surfaces of the flap may lead to a reduction of flap side edge noise.