21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-3.6.2

EFFECTS OF USING BI-FLAP-SYSTEM ON THE IMPROVEMENT OF AERODYNAMICS OF A SWEPTBACK WING

Xin D. -D., Li Yuan*
Beijing University of Aeronautics, PRC; *Chinese Acad. Of Sciences, PRC

Keywords: bi-flap-system, aerodynamics of a sweptback wing

The bi-flap-system is a device comprising an apex-flap and leading-edge-flaps located on the forepart and after part of a 74 degree delta wing respectively in this study. Through controlling the vortex separated from the leading-edge-flaps by that from the apex-flap, the aerodynamic characteristics of the wing can be improved on enhancing the ability of reducing drag ,increase of lift-drag ratio and the improvement of the nature of wing stall. This concept of vortex-control is based on using double vortex system in dominating the flow past wing, which differs from that by using single vortex like the wing-strake and vortex-flap. The superiority of using bi-flap-system to others and its principle of vortex control are interpreted in this paper through comparisons among experimental results which were verified by the numerical solution of the Navier-Stokes equations with the turbulent effect preliminarily considered at Re = 1x10^6 . According to our former investigations, the bi-flap-system is effective even at high speed up to Mach no. = 2.0 and in the case of wing-body combination.

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