How to Cite

DEFECT FUNCTION MODELS FOR THE WAVE BOUNDARY LAYERS. (2020). Coastal Engineering Proceedings, 36v, waves.2.


The boundary layer flow induced by surface waves has been extensively investigated due to its significance in engineering applications such as sediment transport and hydrodynamic forces on subsea structures. Several forms of defect functions (referred to as DF hereafter) were developed in the past decades, e.g. Sleath (1970, 1982), Nielsen (1985, 2016) and etc., due to their good efficiency in the description of the velocity distribution in one dimensional wave boundary layer (WBL). In this work, two forms of DFs are proposed: (i) DF-I describes the velocity distributions and bottom shear stresses in phase space with 4 model parameters; (ii) DF-II describes the maximum WBL profile with 3 model parameters. A number of datasets to support the validation of the DFs were obtained through experimental and numerical tests. Two sets of experiments were conducted individually in a free-surface-wave flume located in Dalian University of Technology and an oscillating-flow flume located in the University of Western Australia. For the free surface wave tests, the velocity was measured.

Recorded Presentation from the vICCE (YouTube Link):


Dixen, M. Hatipoglu, F. Sumer, B. M. & Jørgen, F. (2008): Wave boundary layer over a stone-covered bed. Coastal Eng. 55(1), 1-20.

Nielsen, P. (1985): On the structure of oscillatory boundary layers. Coastal Eng. 9(3), 261-276.

Nielsen, P. (2016): 1DV structure of turbulent wave boundary layers. Coastal Eng. 112, 1-8.

Sleath, J. (1970): Velocity measurements close to the bed in a wave tank. J. Fluid Mech. 42(1), 111-123.

Sleath, J. (1982): The effect of jet formation on the velocity distribution in oscillatory flow over flat beds of sand or gravel. Coastal Eng. 6(2), 151-177.

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