Time scale of scour around a pile in combined waves and current

Thor Ugelvig Petersen, B. Mutlu Sumer, Jørgen Fredsøe

    Research output: Contribution to conferencePaperResearchpeer-review


    The time scale of the scour process around a circular vertical pile is studied in combined waves and current. A series of tests were carried out in a flume with pile diameters 40 mm and 75 mm, in both steady current, waves and combined waves and current. In the combined wave and current flow regime the waves and the current were co-directional. All the tests were conducted in the live bed regime.
    The time scale of scour in combined waves and current is governed by three parameters, namely the current-velocity-to-wave-velocity ratio (Ucw), the Keulegan–Carpenter number (KC) and Shields parameter (Θw ). The time scale of scour increases significantly when even a slight current is superimposing on a wave. The KC dependence of the time scale T is mainly observed for low values of Ucw in the wave dominated
    regime. For Ucw values larger than 0.4 no clear KC dependency was observed. The time scale decreases with increasing Θw over the entire range of Ucw.

    Original languageEnglish
    Publication date2012
    Number of pages8
    Publication statusPublished - 2012
    EventICSE-6: 6th International Conference on Scour and Erosion - Paris, France
    Duration: 27 Aug 201231 Aug 2012



    Bibliographical note



    • Coastal structures
    • Slender piles
    • Offshore structures
    • Pile
    • Scour
    • Time scale
    • Vertical cylinder
    • Steady current
    • Wave
    • Offshore wind farm


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