VELOCITY DEFECT LAW IN THE WAVE BOTTOM BOUNDARY LAYER

Tiago Abreu, H. Michallet, P. A. Silva, F. Sancho, P. Nielsen

Abstract


This work presents a simple method based on the defect law (Nielsen,1992) to reproduce the velocity vertical profile within the wave bottom boundary layer. The model results agree fairly well with the ADVP measurements and show that the defect law reproduces typical features of the oscillatory boundary layer: the velocity magnitude first increases with distance from the bed, with an overshoot at approximately 3 cm above the bed. There is a phase shift in the velocity that is maximum at about 1cm above the bed. Processing of the bed shear stress as well as velocities estimates within the sheet flow layer is under progress. (e.g. Ruessink et al., submitted)

Keywords


boundary layer; experiment; vertical profile

References


Abreu, T., Silva, P.A., Sancho, F. and Temperville, A. (2010). Analytical approximate wave form for asymmetric waves. CoastalEngineering, 57, 656-667.http://dx.doi.org/10.1016/j.coastaleng.2010.02.005

Nielsen, P., 1992. Coastal Bottom Boundary Layers and Sediment Transport. World Scientific, 324 pp.

Silva, P.A., Abreu, T., Van der A, D.A., Sancho, F., Ruessink, B.G., Van der Werf, J.J. and Ribberink, J.S. (Submitted). Sediment transport in non-linear skewed oscillatory flows: the Transkew experiments. Journal of Hydraulic Research.

B.G., Ruessink, Michallet, H., Abreu, T., Sancho, F., Van der A, D.A., Van der Werf, J.J. and Silva, P.A. (Submitted). Observations of velocities, sand concentrations, and fluxes under monochromatic velocity-asymmetric oscillatory flows. Journal of Geophysical Research.


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