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Investigation of the swash zone evolution at wave time scale

Astier, Jessica and Astruc, Dominique and Lacaze, Laurent and Eiff, Olivier Investigation of the swash zone evolution at wave time scale. (2012) In: The 33rd International Conference on Coastal Engineering, 1 July 2012 - 6 July 2012 (Santander, Spain).

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Abstract

The present work is dedicated to the study of the swash zone bed evolution at a high temporal and spatial resolution to investigate single-wave to wave-group time scales. The measurements are obtained in a large scale wave flume with a 1/15 sloping beach of well-sorted sand (d₅₀= 250 μm). The wave regime considered is a random Jonswap spectrum (peak enhancement factor γ = 3.3, significant wave height Hₛ= 0.53 m and peak period Tₚ = 4.14 s). A stereoscopic technique (Astruc et al., 2012) has been used to measure the sand bed evolution in the swash zone over a 3×2 m² area. This experiment allows us to capture the swash dynamics and the bottom evolution at the different temporal scales. The results prove the strong correlation between wave forcing and swash zone response over the entire experiment, even if the bottom evolves. At shorter time scales, we can observe the signature of gravity and infragravity waves. We showed that at both time scales, the erosion process exhibits a strong variability in time as accretion and erosion events are observed. The spatial variability of the bottom evolution is stronger at gravity than at infragravity time scales. These results reinforce the now-admitted idea that the mean evolution of the sand bed in the swash zone is the result of several events of a very different nature, which themselves depend on the details of the swash hydrodynamics.

Item Type:Conference or Workshop Item (Paper)
Additional Information:Proceedings of the International Conference on Coastal Engineering. Coasts, Oceans, Ports & Rivers Institute. ISSN: 2156-1028
Audience (conference):International conference proceedings
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
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Deposited By: Laurent LACAZE
Deposited On:02 Oct 2013 14:02

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