Effect of micron-sized roughness and sound receptivity on a swept wing boundary-layer transition

Yasuaki Kohama, Hajime Watanabe

    Research output: Contribution to journalArticle

    Abstract

    The effect of micron-sized roughness in the leading edge region on a swept wing boundary-layer transition is examined experimentally in detail. By applying sound waves from a loud speaker, sound receptivity to turbulent transition is also investigated. Results showed that such a minute roughness element (k=45 μm in height, 1 mm in diameter, k/δ=0.23) placed at x=40 mm resulted in early transition. In the case that no transition enhancement was observed in the presence of a single roughness element, early transition also occurred with sound excitation. Low frequency disturbance f1 responded strongly to the sound frequency, in particular, to the direction of the sound waves. Critical spacing of roughness elements where the transition is amplified the most seems to exist in the range of λ/δ = 1.3. It is also noted that no enhancement of transition occurs when the roughness element is placed beyond 20% of the chord length.

    Original languageEnglish
    Pages (from-to)2269-2276
    Number of pages8
    JournalNippon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B
    Volume62
    Issue number598
    DOIs
    Publication statusPublished - 1996 Jan 1

    ASJC Scopus subject areas

    • Condensed Matter Physics
    • Mechanical Engineering

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