3D scour below pipelines under waves and combined waves and currents

Liang Cheng, K. Yeow, Z. Zang, F. Li

    Research output: Contribution to journalArticle

    48 Citations (Scopus)

    Abstract

    This paper presents the results of an experimental investigation on three-dimensional local scour below a rigid pipeline subjected to wave only and combined wave and current conditions. The tests were conducted in a conventional wave flume. The major emphasis of the investigation was on the scour propagation speed (free span expansion rate) along the pipeline after local scour was initiated at a controlled location. The effects of flow ratio (steady current velocity vs. combined waves/current velocity), flow incidence angle and pipeline initial embedment depth on free span expansion rate were investigated. It was observed that the scour along the pipeline propagated at a constant rate under wave only conditions. The scour propagation rate decreased with increasing embedment depth, however, increased with the increasing Keuglegan-Carpenter (KC) number. Under combined wave and current conditions, the effect of velocity ratio on scour propagation velocity along the pipeline was quantified. Empirical relationships between the scour propagation rate (Vh) and key parameters such as the KC number and embedment depth (e/D) were established based on the testing results. © 2013 Elsevier B.V.
    Original languageEnglish
    Pages (from-to)137-149
    Number of pages13
    JournalCoastal Engineering
    Volume83
    Early online date6 Nov 2013
    DOIs
    Publication statusPublished - Jan 2014

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    Cheng, Liang ; Yeow, K. ; Zang, Z. ; Li, F. / 3D scour below pipelines under waves and combined waves and currents. In: Coastal Engineering. 2014 ; Vol. 83. pp. 137-149.
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    3D scour below pipelines under waves and combined waves and currents. / Cheng, Liang; Yeow, K.; Zang, Z.; Li, F.

    In: Coastal Engineering, Vol. 83, 01.2014, p. 137-149.

    Research output: Contribution to journalArticle

    TY - JOUR

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    AU - Yeow, K.

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    AU - Li, F.

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    AB - This paper presents the results of an experimental investigation on three-dimensional local scour below a rigid pipeline subjected to wave only and combined wave and current conditions. The tests were conducted in a conventional wave flume. The major emphasis of the investigation was on the scour propagation speed (free span expansion rate) along the pipeline after local scour was initiated at a controlled location. The effects of flow ratio (steady current velocity vs. combined waves/current velocity), flow incidence angle and pipeline initial embedment depth on free span expansion rate were investigated. It was observed that the scour along the pipeline propagated at a constant rate under wave only conditions. The scour propagation rate decreased with increasing embedment depth, however, increased with the increasing Keuglegan-Carpenter (KC) number. Under combined wave and current conditions, the effect of velocity ratio on scour propagation velocity along the pipeline was quantified. Empirical relationships between the scour propagation rate (Vh) and key parameters such as the KC number and embedment depth (e/D) were established based on the testing results. © 2013 Elsevier B.V.

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