Flow separation on multi-element high-lift airfoils can be a complicated function of geometry and flight conditios,and can not be predicted reliably at his time.Previous reports ahve shown that certain high-lift configurations exhibit bundary-laryer separation on the flap at low angles of attack,while fullyattached flap flow occurs nearmaximumlift conditions [1],[2].In these cases,altering the geometrical confiuration to avoid low angle-of-attack flap separation had the detrimental effect of reducing maximum lift.in situations like this,one possible means of maintaining high maxiumu-lift values while attenuating boundary-layer separation at low angles of attack is to employ flap-mounted,low-profile,vortex generators.
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