Effect of oscillation on boundary-layer development with adverse pressure gradients

An experimental study has been conducted to investigate the effects of oscillation, of varying amplitude (0 to 0.03 m) and frequency (0 to 6 Hz), on the boundary-layer development of a flat plate under the influence of adverse pressure gradients. The Reynolds number was 106 based on the flat plate chord length. The study employed a subsonic wind tunnel facility at a freestream velocity of 16 m/s. A cylinder placed at various locations over the flat plate within the boundary layer was used to create the effects of adverse pressure gradients. Surface pressures were measured along the centerline of the flat plate to study the flow quantitatively. Oil flow visualizations were also obtained to examine the flow qualitatively. Boundary-layer surveys were conducted to examine the effect of oscillation on the mean velocity, turbulence intensity, and boundary-layer thickness profiles.