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Measurements of near‐bed intra‐wave sediment entrainment above vortex ripples
Author(s) -
Thorne Peter D.,
Davies Alan G.,
Williams Jon J.
Publication year - 2003
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2003gl018427
Subject(s) - entrainment (biomusicology) , wave flume , flume , sediment transport , vortex , geology , turbulence , sediment , vortex shedding , seabed , mechanics , bedform , geomorphology , breaking wave , physics , flow (mathematics) , oceanography , reynolds number , wave propagation , optics , acoustics , rhythm
In general, descriptions of suspended sediment transport beneath surface waves are based on the turbulent diffusion concept. However, it is recognised that this approach is questionable for the suspension of sediment when the seabed is rippled. In this case, at least if the ripples are sufficiently steep, the entrainment process is likely to be well organised, and associated with vortex formation and shedding from the ripples. To investigate the entrainment process above ripples, a study was carried out in a large‐scale wave flume facility. Utilising acoustic techniques, visualisations of the intra‐wave sediment entrainment above vortex ripples have been generated. The observations provide a detailed description of entrainment, which is interpreted here in relation to the process of vortex formation and shedding. It is anticipated that such measurements will contribute to the development of improved physical process models of sediment transport in the rippled bed regime.