Sediment transport and beach morphodynamics induced by free long waves, bound long waves and wave groups

Baldock, T. E., Manoonvoravong, P. and Pham, K. S. (2010) Sediment transport and beach morphodynamics induced by free long waves, bound long waves and wave groups. Coastal Engineering, 57 10: 898-916. doi:10.1016/j.coastaleng.2010.05.006


Author Baldock, T. E.
Manoonvoravong, P.
Pham, K. S.
Title Sediment transport and beach morphodynamics induced by free long waves, bound long waves and wave groups
Journal name Coastal Engineering   Check publisher's open access policy
ISSN 0378-3839
1872-7379
Publication date 2010-10
Sub-type Article (original research)
DOI 10.1016/j.coastaleng.2010.05.006
Volume 57
Issue 10
Start page 898
End page 916
Total pages 19
Editor Hans F. Burcharth
Place of publication Amsterdam, Netherlands
Publisher Elsevier Science B.V.
Collection year 2011
Language eng
Formatted abstract
New laboratory data are presented on the influence of free long waves, bound long waves and wave groups on sediment transport in the surf and swash zones. As a result of the very significant difficulties in isolating and identifying the morphodynamic influences of long waves and wave groups in field conditions, a laboratory study was designed specifically to enable measurements of sediment transport that resolve these influences. The evolution of model sand beaches, each with the same initial plane slope, was measured for a range of wave conditions, firstly using monochromatic short waves. Subsequently, the monochromatic conditions were perturbed with free long waves and then substituted with bichromatic wave groups with the same mean energy flux. The beach profile changes and net cross-shore transport rates were extracted and compared for the different wave conditions, with and without long waves and wave groups. The experiments include a range of wave conditions, e.g. high-energy, moderate-energy, low-energy waves, which induce both spilling and plunging breakers and different turbulent intensities, and the beaches evolve to form classical accretive, erosive, and intermediate beach states. The data clearly demonstrate that free long waves influence surf zone morphodynamics and promote increased onshore sediment transport during accretive conditions and decreased offshore transport under erosive conditions. In contrast, wave groups, which can generate both forced and free long waves, generally reduce onshore transport during accretive conditions and increase offshore transport under erosive conditions. The influence of the free long waves and wave groups is consistent with the concept of the relative fall velocity, H/wsT, as a dominant parameter controlling net beach erosion or accretion. Free long waves tend to reduce H/wsT, promoting accretion, while wave groups tend to increase the effective H/wsT, promoting erosion.
© 2010 Elsevier B.V. All rights reserved
Keyword Long waves
Sediment transport
Surf zone
Surf beat
Wave groups
Swash
Beach morphodynamics
Surf-zone turbulence
Gravity-waves
Mass-transport
Coastal lagoon
Edge waves
Bars
Breakpoint
Generation
Suspension
Breaking
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 2011 Collection
 
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Citation counts: TR Web of Science Citation Count  Cited 14 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 20 times in Scopus Article | Citations
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Created: Sun, 12 Sep 2010, 00:05:54 EST