scholarly journals Sediment resuspension mechanisms associated with internal waves in coastal waters

2008 ◽  
Vol 113 (C10) ◽  
Author(s):  
M. Stastna ◽  
K. G. Lamb
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. Mendes ◽  
J. C. B. da Silva ◽  
J. M. Magalhaes ◽  
B. St-Denis ◽  
D. Bourgault ◽  
...  

AbstractInternal waves (IWs) in the ocean span across a wide range of time and spatial scales and are now acknowledged as important sources of turbulence and mixing, with the largest observations having 200 m in amplitude and vertical velocities close to 0.5 m s−1. Their origin is mostly tidal, but an increasing number of non-tidal generation mechanisms have also been observed. For instance, river plumes provide horizontally propagating density fronts, which were observed to generate IWs when transitioning from supercritical to subcritical flow. In this study, satellite imagery and autonomous underwater measurements are combined with numerical modeling to investigate IW generation from an initial subcritical density front originating at the Douro River plume (western Iberian coast). These unprecedented results may have important implications in near-shore dynamics since that suggest that rivers of moderate flow may play an important role in IW generation between fresh riverine and coastal waters.


2019 ◽  
Vol 51 (1) ◽  
pp. 129-154 ◽  
Author(s):  
Leon Boegman ◽  
Marek Stastna

Large-amplitude internal waves induce currents and turbulence in the bottom boundary layer (BBL) and are thus a key driver of sediment movement on the continental margins. Observations of internal wave–induced sediment resuspension and transport cover significant portions of the world's oceans. Research on BBL instabilities, induced by internal waves, has identified several mechanisms by which the BBL is energized and sediment may be resuspended. Due to the complexity of the induced currents, process-oriented research using theory, direct numerical simulations, and laboratory experiments has played a vital role. However, experiments and simulations have inherent limitations as analogs for oceanic conditions due to disparities in Reynolds number and grid resolution, respectively. Parameterizations are needed for modeling resuspension from observed data and in larger-scale models, with the efficacy of parameterizations based on the quadratic stress largely determining the accuracy of present field-scale efforts.


2020 ◽  
Author(s):  
Alexander Soloviev ◽  
Breanna Vanderplow ◽  
Cayla Dean

Abstract Mixing caused by the solitary internal waves or solitons in stratified coastal waters is a primary cause of sediment resuspension and transport. Theoretical, experimental, and modeling studies of solitons have focused on nonlinear wave dynamics to explain their main features. However, the 3D cascade of energy from breaking internal wave solitons to turbulence and mixing in the wave induced wake has received less attention. Observations on the California shelf with a spatially distributed fiber optic sensing system revealed coherent structures in the wake of solitary internal waves breaking on the continental slope1,2. Here, we reproduced this phenomenon with a computational fluid dynamics model. The model demonstrated that the coherent structures in the wake of the breaking solitary internal wave are counterrotating helices. The concept of helicity3 as a topological invariant and a measure of the lack of mirror symmetry of the flow can explain the helical nature of these coherent structures4. Both observational and modeling results are consistent with this theoretical conjecture. These coherent structures have a substantial effect on the sediment transport in the bottom boundary layer, formation of nepheloid layers5, and nutrient fluxes.


Chemosphere ◽  
2019 ◽  
Vol 235 ◽  
pp. 651-661 ◽  
Author(s):  
Chrystelle Bancon-Montigny ◽  
Catherine Gonzalez ◽  
Sophie Delpoux ◽  
Muriel Avenzac ◽  
Sylvie Spinelli ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document