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EXPERIMENTAL INVESTIGATION OF STEADY CIRCULATION CONTROL BLOWING OVER A ROUNDED WINGTIP

Adam M. Edstrand
Department of Mechanical Engineering Florida Center for Advanced Aero-Propulsion, Florida State University 2003 Levy Ave, Tallahassee, FL 32310, United States of America

Louis N. Cattafesta III
Department of Mechanical Engineering Florida Center for Advanced Aero-Propulsion, Florida State University 2003 Levy Ave, Tallahassee, FL 32310, United States of America

Abstrakt

Wingtip vortices are an adverse by-product of lift generation on an airfoil. To study the control of these vortices, a semi-span NACA 0012 airfoil model with a rounded wingtip is mounted in an open-jet wind tunnel. The wake of the vortex is measured from 1.5 to 5.25 chords downstream of the leading edge of the airfoil via stereo particle image velocimetry. Spatially uniform and segmented steady blowing from a chordwise slot on the suction side of the rounded wingtip are used as control. For uniform blowing, there is a peak reduction in the average of the maximum swirl velocity, associated with the wake-hazard problem, by nearly 30%. However, there is a monotonic increase in circulation with increasing momentum coefficient, increasing the strength of the vortex and potentially modifying the lift on the wing. The segmented-steady blowing configuration had minimal effect on circulation for low momentum coefficient values while reducing the maximum of the time-averaged swirl velocity by 20% for a momentum coefficient of 0.0023.