Influence of Continuous Jet at the Lower Surface on Airfoil Aerodynamic Performance

Abstract

AbstractA new control method using jet to control airfoil is proposed through arranged jet on the lower surface of the trailing edge (LSTE jet). Commercial computational fluid dynamics software CFX was utilized to compute the flow field around the airfoil. Through comparing the changes of the flow field before and after the jet was applied, we studied the flow control effects and laws of LSTE jet. We also studied the change rule of lift and drag characteristics with jet position, momentum coefficient and forward angle. Our results showed that, first, LSTE jet caused low-pressure zone at airfoil trailing edge and forced the flow to deflect downward, which increased the effective curvature of the airfoil and so increased the lift. Second, aerodynamic coefficients were sensitive to all of the three parameters of jet position, momentum coefficient and forward angle. LSTE jet closer to the trailing edge caused greater lift and less drag because it created a larger low-pressure area. At small angle of attack, lift coefficient increased as jet momentum coefficient increased and had good linearity. The best forward angle was 70°, at which point the lift was greatest and the drag was least. In general, LSTE jet can effectively influence aerodynamic characteristics of NACA0012 airfoil and had a good application prospect in flow control of aircraft.KeywordsActive flow controlLower surface jetNACA12Increasing liftSmall angle of attack