The influence of actuator spacing on separation control using fluidic oscillators is experimentally investigated on a wall-mounted hump. Momentum inputs up to C μ = 2.5 % are tested at four different spacings ( Δ z / c = 2.27 , 4.55, 6.82, and 9.09%), at Re = 1.0 10 6 and M = 0.09 . For all spacings, the control authority is characterized by two distinct regimes associated with boundary-layer control and circulation control. The two narrow spacings show steep control authority gradients in the transition between boundary-layer control and circulation control. The time-averaged flowfields from spanwise stereoscopic particle image velocimetry (PIV) vary significantly between the presented spacings, but the circulation normalized by mass flow rate per jet remains constant for a given momentum input in the boundary-layer control regime. When the spacing is too small for a given oscillator design, the introduced vorticity is unorganized and actuation is less effective for a given momentum input. Once the flow is attached, the circulation reduces for larger momentum inputs (circulation control). This indicates a connection between increased control authority and decreased circulation in the circulation control regime. These findings are supported by novel circulation metrics that describe the level of organization in the flowfield.


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    Title :

    Connection Between Flow Structure and Separation Control for Various Fluidic Oscillator Spacings


    Contributors:

    Published in:

    AIAA Journal ; 60 , 7 ; 4227-4239


    Publication date :

    2022-07-01




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English





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