Mixing Mechanism of a Discrete Co-Flow Jet Airfoil
نویسندگان
چکیده
The flow mechanism leading to the enhanced performance of a discrete co-flow jet (dCFJ) airfoil is investigated. Flow visualization and DPIV are used to analyze the difference between the flow along discrete jets and over the tabs used for discretization of the slot jet. Results show that the entrainment is uniform over the leading jet as long as the tab size is small enough. The jets expand spanwise, inducing downward momentum toward the surface of the airfoil. Combined with the momentum increase due to the CFJ, the dCFJ is shown to dramatically increase lift up to 150% from the baseline airfoil and delay separation up to 10 angle of attack. More results and analysis will be presented in the final paper. Nomenclature AoA Angle of attack C Chord length CFJ Co-flow jet CC Circulation control CL Lift coefficient CD Drag coefficient Cμ Jet momentum coefficient D Drag L Lift M Mach number OF Obstruction factor p Static pressure Pt Total pressure Re Reynolds number S Wing span area m Jet mass flow rate u,v,w Velocity components in x-, y-, and z-direction V Velocity vector x,y,z Chord, normal and spanwise directions, with respect to the airfoil Subscripts: ∞ Freestream j Jet Greek Letters: γ Ratio of specific heats ρ Density α Angle of attack β Angle between slot surface and the line normal to chord 41st AIAA Fluid Dynamics Conference and Exhibit 27 30 June 2011, Honolulu, Hawaii AIAA 2011-3097 Copyright © 2011 by by all the authors of this paper. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission.
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