Transverse vortex-induced vibrations of a near-wall cylinder under oblique flows

Zhipeng Zang, Tongming Zhou

    Research output: Contribution to journalArticle

    5 Citations (Scopus)
    158 Downloads (Pure)

    Abstract

    Transverse vortex-induced vibrations (VIVs) of a near-wall cylinder under oblique flows are studied experimentally in a water flume for both increasing and decreasing velocities. The VIV responses and the wake flow patterns around the cylinder are measured with a synchronous measurement system and a PIV. The validity of the Independence Principle (IP) for a cylinder in proximity to a wall is examined in terms of the vibration amplitude, frequency and critical normal reduced velocity. The results show that the combinations of the gap ratio and oblique angle have significant effect on the VIV response of a circular cylinder. The IP is found to be valid in predicting the VIV response for small oblique angles (θ≤30°) and large gap ratios (e/D≥0.8) whereas for large oblique angles (θ>30°) or small gap ratios (e/D<0.8), the deviations from the IP are pronounced. The upper and lower critical normal reduced velocities for the onset of VIV are obtained for both increasing and decreasing velocities. Empirical relationships between the correction factor of the critical normal reduced velocity and gap ratio and the oblique angles (θ≤45°) are established. Based on the analyses of the wake flow patterns obtained by PIV, it is found that the difference in the onset of VIV for increasing and decreasing velocities corresponds to different vortex shedding modes at the initial branch: the 2S vortex shedding mode for increasing velocity and the C(2S) mode for decreasing velocity.

    Original languageEnglish
    Pages (from-to)370-389
    Number of pages20
    JournalJournal of Fluids and Structures
    Volume68
    DOIs
    Publication statusPublished - 1 Jan 2017

    Fingerprint Dive into the research topics of 'Transverse vortex-induced vibrations of a near-wall cylinder under oblique flows'. Together they form a unique fingerprint.

  • Projects

    Cite this