Modification of Blade Vortex Interactions Using Leading Edge Blowing

This paper investigates the effectiveness of leading-edge blowing (LEB) active flow control for modifying the vortex induced vibrations induced on an airfoil by the wake of a circular cylinder. The airfoil was allowed to oscillate perpendicular to the fluid flow direction in response to the impinging Von-Karman street. The flow field was simultaneously captured using Digital Particle Image Velocimetry (DPIV) and accelerometer measurements in a time-resolved sense. The results indicate that LEB can significantly reduce the degree of unsteady loading due to the blade vortex interaction (BVI). In some cases, the LEB jet appears to break the coherency of a vortex incident on the airfoil, and in other cases it appears to increase the mean standoff distance of the vortex as it convects over the airfoil surface.