Recent studies on boundary-layer control with microvortex generators suggest that the microramp should not be simply treated as a traditional streamwise vortex-inducing device. Here, the wake organization downstream of the microramp and its function of fluid redistribution are investigated with a large-eddy simulation at Mach 2.7. It is confirmed by passive scalar convection and streamline tracing that the fluid composing the wake is basically collected from a thin layer close to the wall, particularly beneath 20% of the boundary-layer thickness here, which is responsible for the momentum deficit and low-density features of the wake, as well as the later complex wake evolution. Thus, the microramp has actually worked as a novel near-wall fluid collector, depriving the inner part of the incoming boundary layer, and assembles it into the wake. When developing downstream, the shear induced Kelvin-Helmholtz vortex grows and pairs quickly upon the wake, giving birth to a train of large-scale hairpin vortices with a typical frequency of St=0.57. The similarity between the local density and passive scalar distribution patterns suggests the advection of the collected low-momentum fluid along with the large-scale vortices is the main reason for the intermittent wake structures presented in the previous studies.


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    Titel :

    Fluid Redistribution in the Turbulent Boundary Layer Under the Microramp Control



    Erschienen in:

    AIAA journal ; 53 , 12


    Erscheinungsdatum :

    2015




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Print


    Sprache :

    Englisch


    Schlagwörter :

    Klassifikation :

    BKL:    55.50 Luftfahrzeugtechnik / 55.60 Raumfahrttechnik / 55.60 / 50.93 / 55.50 / 50.93 Weltraumforschung
    Lokalklassifikation TIB:    770/7040



    Fluid Redistribution in the Turbulent Boundary Layer Under the Microramp Control

    Wang, B. / Liu, W. D. / Sun, M. B. et al. | AIAA | 2015




    Microramp Control of Supersonic Oblique Shock-Wave/Boundary-Layer Interactions

    Babinsky, H. / Li, Y. / Ford, C. W. Pitt | AIAA | 2009


    Influence of a Microramp Array on a Hypersonic Shock-Wave/Turbulent Boundary-Layer Interaction

    Schreyer, Anne-Marie / Sahoo, Dipankar / Williams, Owen J. H. et al. | AIAA | 2021