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Numerical investigation of internal wave‐induced sediment motion: Resuspension versus entrainment
Author(s) -
Olsthoorn Jason,
Stastna Marek
Publication year - 2014
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 - 10.1002/2014gl059826
Subject(s) - entrainment (biomusicology) , mechanics , dimensionless quantity , bubble , boundary layer , sediment transport , geology , bursting , sediment , instability , internal wave , physics , geomorphology , neuroscience , rhythm , acoustics , biology
We present numerical simulations of near‐bed instability induced by internal waves shoaling over topography using a model with an explicit representation of the sediment concentration. We find that not all separation bubble‐bursting events lead to resuspension, though all lead to significant transport out of the bottom boundary layer. This transport can significantly enhance chemical exchange across the bottom boundary layer. When resuspension occurs, we find that it is largely due to two‐dimensional evolution of the separation bubble during the bursting process. Three‐dimensionalization occurs once the resuspended sediment cloud is transported out of the bottom boundary layer, and hence, redeposition is strongly influenced by three‐dimensional effects. We derive a criterion for resuspension over a linearly sloping bottom in terms of two dimensionless parameters that encapsulate the sediment properties.