Turbulence-Resolving Simulations of the Plunge Phenomenon in a Stratified Ambient
Abstract
Theoretical and experimental interest in transport and deposition of sediments from rivers to oceans has increased rapidly over the last two decades. The marine ecosystem is strongly affected by mixing at river mouths, with for instance anthropic actions like pollutant spreading. Particle-laden flows entering a lighter ambient fluid (hyperpicnal flows) can plunge at a sufficient depth and their deposits might preserve an important record across a variety of climatic and tectonic settings. Several studies were carried out in order to understand this complex phenomenon using classic box models, natural deposit records and laboratory experiments.
The present work provides valuable spatio-temporal information generated by turbulence-resolving 3D simulations of hyperpicnal plumes over a bed slope in a saline environment. Schuch et al. (2018) provide information about the flow entering in a freshwater channel, however, the present simulations are a continuation of the previous work. The numerical simulations are performed with the high-order flow solver Incompact3d, which solved the incompressible Navier-Stokes equations on a Cartesian mesh using high-order finite-difference schemes. Several scalar transport equations under the Boussinesq approximation are used for the concentrations of particles and salinity. The temporal evolution of plunge and front position, suspended material, deposition rate, entrainment coefficient and densimetric Froude number of the underflow will be discussed.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMOS13C1492S
- Keywords:
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- 1824 Geomorphology: general;
- HYDROLOGYDE: 3002 Continental shelf and slope processes;
- MARINE GEOLOGY AND GEOPHYSICSDE: 3022 Marine sediments: processes and transport;
- MARINE GEOLOGY AND GEOPHYSICSDE: 3045 Seafloor morphology;
- geology;
- and geophysics;
- MARINE GEOLOGY AND GEOPHYSICS