Unsteady Effects of Blowing over Actuated Surfaces Using Phase-Locked Particle Image Velocimetry

Abstract

An experimental study is conducted to investigate the effects of upper-surface trailing-edge blowing on a low-aspect-ratio rectangular wing with an actively actuated flap. Two wing configurations, the wing with a baseline flap and a dual-radius flap, are wind-tunnel tested at three spanwise locations to investigate the three-dimensional and unsteady effects of blowing during flap actuation at a freestream Reynolds number (based on the airfoil chord) of [Formula: see text]. Two-dimensional and stereoscopic phase-locked particle image velocimetry (PIV) measurements are used to collect data during flap actuation at different actuation speeds and blowing intensities. Proper orthogonal decomposition and modified Q criterion are used to analyze the PIV data. The wake dynamics reveal that flap actuation contributes to tip-vortex strengthening when active blowing is not present. The combination of flap actuation and active continuous blowing is more effective in controlling the boundary layer compared to the flap at rest for the same blowing intensities.