A comparison between synthetic jets and continuous jets

Experimental measurements and flow visualization of synthetic jets and continuous jets with matched Reynolds numbers are described. Although they have the same profile shape, synthetic jets are wider and slower than matched continuous jets. The synthetic jets are examined at higher Reynolds numbers than previously studied and over a large range of dimensionless stroke lengths. Nomenclature b cross-stream location where velocity is 0.5Ucl h slot width f driving frequency L0 stroke length = R T=2 0 u0 t ð Þdt Q volume flux Q0 U0h for synthetic jet, and Q0 = Uaveh for continuous jet Reh Reynolds number of continuous jet=Uaveh/m ReU0 Reynolds number of synthetic jet=U0h/m t time (with zero at start of blowing stroke) T driving period=1/f u measured instantaneous velocity U time-averaged velocity Uave time-averaged slot velocity for continuous jet Ucl time-averaged centerline velocity u0(t) centerline or cross-stream-averaged velocity at x=0 for synthetic jet umax maximum of u0(t) U0 L0f x streamwise coordinate y cross-stream coordinate m kinematic viscosity