21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-3.9.4

IMPROVING THE AERODYNAMIC EFFICIENCY OF A WING BY ACOUSTIC EXCITATION

Ahmed N. A., Archer R. D., Heywood M.
University of New South Wales, Australia

Keywords: aerodynamic efficiency, wing, acoustic excitation

Various active and passive techniques of controlling or suppressing boundary layer have evolved with varying degrees of success since the introduction of the boundary layer concept at the turn of this century. The manipulation of boundary layer flow by acoustic excitation is, however, more of a recent phenomenon and one of the least developed. Most of thee work to date has been primarily on two dimensional flat plates or airfoils. In this paper, we look at the performance of a constant NACA0012 symmetric half wing of effective aspect ratio of 4 under external acoustic excitation frequencies ranging from 100 Hz to 3 kHz. Tests were conducted in a open jet low speed wind tunnel when flow has separated on the wing at 16, 17, 18 and 19 degrees of angle of incidence and three different air speeds of 7, 10 and 25mls respectively. It is found that lift is significantly improved and drag is appreciably reduced thereby improving the lift to drag ratio of the wing to nearly twice its corresponding unexcited value. Such improvement, however, is found to be frequency and Reynolds number dependent.

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