the effect of downstream suction on the delta wing leading-edge vortex zhou ji, jeff marchetta, j....

THE EFFECT OF THE EFFECT OF DOWNSTREAM SUCTION DOWNSTREAM SUCTION ON THE DELTA WING ON THE DELTA WING LEADING-EDGE VORTEXLEADING-EDGE VORTEX

Zhou Ji, Jeff Marchetta, J. Hochstein and Zhou Ji, Jeff Marchetta, J. Hochstein and J. D. MoJ. D. Mo

University of Memphis, Memphis, TN University of Memphis, Memphis, TN 38152, USA38152, USA

K. X. He, and Alan ChowK. X. He, and Alan Chow

Alabama A & M University, Huntsville, Alabama A & M University, Huntsville, AL 35862, USAAL 35862, USA

IntroductionIntroduction

Leading-edge vortex produces vortex Leading-edge vortex produces vortex lift on delta wing.lift on delta wing.

Vortex cores are susceptible to quick Vortex cores are susceptible to quick deterioration by external disturbances.deterioration by external disturbances.

Vortex can be influenced by injecting a Vortex can be influenced by injecting a jet or lateral blowing, etc.jet or lateral blowing, etc.

Vortex is controlled and lengthen by Vortex is controlled and lengthen by suction fan in this work.suction fan in this work.

IntroductionIntroduction

IntroductionIntroduction

IntroductionIntroduction

Experimental Set-upExperimental Set-up

Wind Tunnel: 2Wind Tunnel: 22 foot low speed 2 foot low speed wind tunnel at the University of wind tunnel at the University of MemphisMemphis

20 inch low load driving fan is used 20 inch low load driving fan is used instead of the original driving fan.instead of the original driving fan.

Smoking wire technique is used to Smoking wire technique is used to visualize the leading edge vortex.visualize the leading edge vortex.

Experimental Set-upExperimental Set-up

Half model of delta wing made of Half model of delta wing made of plastic.plastic.

Leading-edge sweep angle: 60Leading-edge sweep angle: 60OO

Chord length at the root: 11-1/2 Chord length at the root: 11-1/2 inchesinches

Adjustable angle of attack: Adjustable angle of attack: 1515oo~35~35oo

Experimental Set-upExperimental Set-up

Experimental parameters:Experimental parameters:

Distance to the fan Distance to the fan dd

Height to the fan Height to the fan hh

Angle of attack Angle of attack Power level of fan (6V or 18V)Power level of fan (6V or 18V)

Reference length: chord length Reference length: chord length cc

Experimental ResultsExperimental Results

=25o, no fan

Experimental ResultsExperimental Results

=25o, d/c=0, h/c=1/8

Experimental ResultsExperimental Results

=30o, no fan

Experimental ResultsExperimental Results

=30o, d/c=0, h/c=1/4

Experimental ResultsExperimental Results

=30o, d/c=0, h/c=1/4, high power

Experimental ResultsExperimental Results

=30o, d/c=0, h/c=1/8

Experimental ResultsExperimental Results

=30o, d/c=0, h/c=3/8

Experimental ResultsExperimental Results

=30o, d/c=0, h/c=0

Experimental ResultsExperimental Results

=25o, d/c=0, h/c=1/4

Experimental ResultsExperimental Results

=25o, d/c=0, h/c=0

Experimental ResultsExperimental Results

=30o, d/c=1/4, h/c=1/4

Experimental ResultsExperimental Results

=30o, d/c=1/2, h/c=1/4

Experimental ResultsExperimental Results

=25o, d/c=1/4, h/c=1/4

Experimental ResultsExperimental Results

=25o, d/c=1/2, h/c=1/4

ConclusionsConclusions

The vortex is enhanced by properly The vortex is enhanced by properly positioned suction fan.positioned suction fan.

As the angle of attack increases, the As the angle of attack increases, the influence becomes very apparent.influence becomes very apparent.

The optimal horizontal position is 0 height The optimal horizontal position is 0 height relative to trailing edge.relative to trailing edge.

The optimal height is the at the vortex core.The optimal height is the at the vortex core. Vortex enhancement increases with the Vortex enhancement increases with the

fan’s speed.fan’s speed.