The present work discusses an experimental investigation into the effect of orifice geometry on the formation and advection of vortical structures associated with a synthetic jet issued into a quiescent flow. Three orifice geometries (namely, rectangular, trapezoidal, and triangular shapes) having the same aspect ratio ( AR = 19 ) and area were tested at a hydraulic diameter-based Reynolds number and a Strouhal number of 7000 and 0.066, respectively. Using a single hot wire, the spanwise distribution of the velocity at the jet orifice plane was first measured. The trapezoidal and triangular orifices exhibited a nonuniform velocity distribution along the orifice, where the velocity was 25 and 130% higher at the smaller cross-section side as compared to the large section side, respectively. Stereoscopic particle image velocimetry was employed to investigate the velocity and vorticity fields downstream of the synthetic jet’s orifice. Vortical, ringlike structures were created at each orifice, where the trapezoidal and triangular orifice geometries resulted in vectoring of these structures toward the larger cross-sectional area of the shape. Axis switching was also observed by each orifice; however, it occurred closer to the orifice for the triangular and trapezoidal orifices when compared to the rectangular orifice. Jet spreading and vorticity dissipation are also presented and were shown to be highly dependent on the orifice geometry.


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    Title :

    Effect of Orifice Geometry on Synthetic Jet Evolution


    Contributors:

    Published in:

    AIAA Journal ; 57 , 7 ; 2783-2794


    Publication date :

    2019-07-01




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English