Two different passive flow control strategies were investigated for a modified NACA 64 3 - 618 airfoil at a chord-based Reynolds number of R e = 64 , 200 and an angle of attack of α = 8.64 deg . For these conditions, the laminar boundary layer separates from the suction side, resulting in a loss of lift and a drag increase. Distributed roughness elements with roughness Reynolds numbers of R e k = 136 and 446 that were mounted near the leading edge and scalloped leading edges with serration amplitudes of 5 and 0.5% of the chord were considered. The large roughness elements and the scalloped leading edge reduce the flow separation and enhance performance. The flow physics are, however, different. For R e k = 446 , the roughness elements result in high-frequency shedding. The shedding results in an accelerated transition of the separated boundary layer. For the scalloped leading edge with 5% serration amplitude, laminar separation bubbles are situated in the leading-edge troughs. The turbulent wedges that originate from these bubbles coalesce near midchord. For a serration amplitude of 0.5%, the separation line is deformed in the spanwise direction in a manner that is reminiscent of stall cells.


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    Titel :

    Numerical Investigation of Passive Separation Control for an Airfoil at Low-Reynolds-Number Conditions


    Beteiligte:
    Gross, A. (Autor:in) / Fasel, H. F. (Autor:in)

    Erschienen in:

    AIAA Journal ; 51 , 7 ; 1553-1565


    Erscheinungsdatum :

    2013-05-17


    Format / Umfang :

    13 pages




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Elektronische Ressource


    Sprache :

    Englisch