Project Title:

Low-Speed Visualization Studies of Vortex Systems on Chine-Forebody/Delta Wing

02.09-0794A
Low-Speed Visualization Studies of Vortex
	Systems on Chine-Forebody/Delta Wing
		Configurations
Vigyan Research Associates, Inc.
30 Research Drive
Hampton, VA 23666
Dhanvada M. Rao  (804-865-1400)
ARC -- NAS2-12780

Abstract:

	 Fore-bodies with vortex-generating side edges or chines blending into highly swept
leading edges are known to stabilize leading edge vortices through aerodynamic coupling
at high angles of attack. However, in post-stall maneuvering flight, chine-vortex
interaction with the wing and vertical tails can lead to roll and yaw sensitivity
together with reduced or negative damping, making the configuration prone to departure.
This research explored the feasibility of decoupling the chine and wing vortices
by applying three alternate geometrical modifications whose effectiveness on a generic,
delta-wing fighter configuration were investigated through low-speed, wind-tunnel
flow visualizations in a broad angle-of-attack and sideslip envelope.
	Smoke visualizations and limited wing-pressure surveys indicated that vortex decoupling
could be achieved by introducing a local discontinuity at the chine and leading-edge
junction and, even more effectively, by deflecting inboard leading-edge flaps.

Potential Commercial Application:

Potential Commercial Application: These results will be used by the national aeronautical
industry involved in tactical aircraft developments of the U.S. Air Force and Navy.