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| Title: | EFFECTS OF ACCELERATION SKEWNESS ON ROUGH BED OSCILLATORY BOUNDARY LAYER FLOW | |
| DOI No: | 10.1142/9789814277426_0131 | |
| Source: | COASTAL ENGINEERING 2008 (pp 1583-1595) | |
| Author(s): | Dominic A. van der A
School of Engineering, University of Aberdeen, Kings College, Aberdeen, AB24 3UE, UK Tom O'Donoghue School of Engineering, University of Aberdeen, Kings College, Aberdeen, AB24 3UE, UK Alan G. Davies School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey, LL59 5AB, UK Jan S. Ribberink Department of Water Engineering & Management, University of Twente, P.O. Box 217, Enschede, 7500 AE, The Netherlands |
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| Abstract: | Acceleration skewness is a feature of the near-bed flow beneath steep and breaking waves. Recent interest in the effects of acceleration skewness on net sediment transport has highlighted a lack of detailed process measurements with which to inform the development of models. This motivated a series of experiments involving sawtooth-type oscillatory flows over fixed rough beds, conducted in a large-scale oscillatory flow tunnel. Detailed velocity measurements were made using Particle Image Velocimetry (PIV). The experimental results show a clear influence of flow acceleration on the near-bed velocity profile and on the shear stress. The greater the acceleration skewness, the higher the ratio of maximum positive (onshore) to maximum negative (offshore) bed shear stress. Predictions based on a 1DV k-ε turbulence-closure model show general good agreement with the measured velocity profiles, near-bed residual current magnitude and the ratios of peak positive to peak negative shear stress. | |
| Full Text: | View full text in PDF format (696KB) | |
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