Large-scale experiments on beach profile evolution and surf and swash zone sediment transport induced by long waves, wave groups and random waves

Baldock, T.E., Alsina, J.A., Caceres, I., Vicinanza, D., Contestabile, P., Power, H. and Sanchez-Arcilla, A. (2011) Large-scale experiments on beach profile evolution and surf and swash zone sediment transport induced by long waves, wave groups and random waves. Coastal Engineering, 58 2: 214-227. doi:10.1016/j.coastaleng.2010.10.006

Author Baldock, T.E.
Alsina, J.A.
Caceres, I.
Vicinanza, D.
Contestabile, P.
Power, H.
Sanchez-Arcilla, A.
Title Large-scale experiments on beach profile evolution and surf and swash zone sediment transport induced by long waves, wave groups and random waves
Journal name Coastal Engineering   Check publisher's open access policy
ISSN 0378-3839
Publication date 2011-02
Sub-type Article (original research)
DOI 10.1016/j.coastaleng.2010.10.006
Volume 58
Issue 2
Start page 214
End page 227
Total pages 14
Place of publication Netherlands
Publisher Elsevier BV
Collection year 2012
Language eng
Abstract New large-scale laboratory data are presented on the influence of long waves, bichromatic wave groups and random waves on sediment transport in the surf and swash zones. Physical model testing was performed in the large-scale CIEM wave flume at UPC, Barcelona, as part of the SUSCO (swash zone response under grouping storm conditions) experiment in the Hydralab III program (Vicinanza et al., 2010). Fourteen different wave conditions were used, encompassing monochromatic waves, bichromatic wave groups and random waves. The experiments were designed specifically to compare variations in beach profile evolution between monochromatic waves and unsteady waves with the same mean energy flux. Each test commenced with approximately the same initial profile. The monochromatic conditions were perturbed with free long waves, and then subsequently substituted with bichromatic wave groups with different bandwidth and with random waves with varying groupiness. Beach profile measurements were made at half-hourly and hourly intervals, from which net cross-shore transport rates were calculated for the different wave conditions. Pairs of experiments with slightly different bandwidth or wave grouping show very similar net cross-shore sediment transport patterns, giving high confidence to the data set. Consistent with recent small-scale experiments, the data clearly show that in comparison to monochromatic conditions the bichromatic wave groups reduce onshore transport during accretive conditions and increase offshore transport during erosive conditions. The random waves have a similar influence to the bichromatic wave groups, promoting offshore transport, in comparison to the monochromatic conditions. The data also indicate that the free long waves promote onshore transport, but the conclusions are more tentative as a result of a few errors in the test schedule and modifications to the setup which reduced testing time. The experiments suggest that the inclusion of long wave and wave group sediment transport is important for improved near-shore morphological modeling of cross-shore beach profile evolution, and they provide a very comprehensive and controlled series of tests for evaluating numerical models. It is suggested that the large change in the beach response between monochromatic conditions and wave group conditions is a result of the increased significant and maximum wave heights in the wave groups, as much as the presence of the forced and free long waves induced by the groupiness. The equilibrium state model concept can provide a heuristic explanation of the influence of the wave groups on the bulk beach profile response if their effective relative fall velocity is larger than that of monochromatic waves with the same incident energy flux.
Keyword Long waves
Wave groups
Sediment transport
Surf zone
Surf beat
Swash zone
Beach morphodynamics
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Civil Engineering Publications
Official 2012 Collection
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 21 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 27 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Fri, 14 Oct 2011, 16:22:36 EST by Tom Baldock on behalf of School of Civil Engineering