Control of the crossflow transition in three-dimensional boundary layer by the small sized roughness alleys

Mitsuru Shimagaki, Shibani Bose, Yasuaki Kohama, Hideo Watanabe, Satoshi Kikuchi

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    1 Citation (Scopus)

    Abstract

    Controlling mechanism of the crossflow dominated transition process in the three-dimensional boundary layer using a small sized roughness is investigated. The stationary crossflow vortices are excited by placing the first roughness elements for the wavelength of λn = 12.5 mm in the spanwise direction, which is equal to the most amplified wavelength under the natural condition, on a swept flat-plate model. The second roughness elements are located three different points between the stationary crossflow vortices. We found that the characteristic asymmetric structure of the stationary crossflow vortices becomes symmetric so that the high shear regions in the vortices are diminished when we located the second roughness at -1/3 of λn with respect to the first roughness. As a result, generation of the high frequency secondary instability is overdue and the delay of turbulent transition has been attained.

    Original languageEnglish
    Pages (from-to)1368-1375
    Number of pages8
    JournalNippon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B
    Volume68
    Issue number669
    DOIs
    Publication statusPublished - 2002 May

    Keywords

    • Flow control
    • Roughness element
    • Secondary instability
    • Shear flow
    • Stationary cross flow vortices
    • Three-dimensional boundary layer
    • Transition

    ASJC Scopus subject areas

    • Condensed Matter Physics
    • Mechanical Engineering

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