21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-3.6.1

EXPERIMENTS ON DELTA WINGS WITH ROUNDED LEADING-EDGE VORTEX FLAPS

Rinoie K.
Cranfield Univ., UK

Keywords: experiments on delta wings, rounded leading-edge vortex flaps

Low speed wind tunnel measurements were done on a 1.15m span 60° delta wing with rounded leading edge vortex flaps. The purpose of the measurements is to assess the benefits of the rounded leading-edge vortex flaps in regard to improving the lift/drag ratio of delta wings. Force and surface pressure measurements were made at a Reynolds number based on a centerline chord of 2x106. The increase in the radius of the rounded leading-edge reduces the drag significantly both with and without flap·· deflection except in the minimum drag region. Deflecting the rounded leading edge vortex flap improves the lift/drag ratio at relatively higher lift coefficients, when compared with the sharp edged vortex flap. The largest improvement in the lift/drag ratio as compared with the sharp edged flat delta wing is more than 50% at a lift coefficient of about 0.6 for the rounded edge delta wing with flaps that were deflected 30° downward.

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