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Impact of sediment-induced stratification and turbulence closures on sediment transport and morphological modelling

Amoudry, Laurent O.; Souza, Alejandro J.. 2011 Impact of sediment-induced stratification and turbulence closures on sediment transport and morphological modelling. Continental Shelf Research, 31 (9). 912-928. 10.1016/j.csr.2011.02.014

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Abstract/Summary

Appropriate descriptions of turbulence are important in predicting sediment transport and seabed evolution. We use here a three-dimensional model to investigate the impacts of sediment-induced stratification, erosion parameterization, and turbulence closures on sediment transport and morphological simulations. The model is implemented in the Proudman Oceanographic Laboratory Coastal Ocean Modelling System (POLCOMS), which couples a hydrodynamic model to the General Ocean Turbulence Model (GOTM) and to a sediment transport model. This sediment transport model calculates both suspended sediment concentrations and bed evolution. A large number of turbulence closures can be tested and we focus on the methods used to calculate the turbulent length scale and the stability functions. Different modelling scenarios are assessed against experimental data of velocity profiles, suspended sediment concentrations, and trench migration in a laboratory flume. Numerical results show that the processes investigated have little impact on the flow velocity profiles, in spite of some differences on the bed shear stress. The only exception is the one-equation turbulence closure, which cannot reproduce velocity profiles appropriately. Sediment-induced stratification, erosion parameterization, and turbulence closures can all have significant impacts on the suspended sediment concentration and the bed evolution. Model-data comparisons are found to be particularly sensitive to the method used to calculate the turbulent length scale

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1016/j.csr.2011.02.014
Programmes: Oceans 2025 > Shelf and coastal processes
POL Programmes > Modelling and observation systems for shelf seas > Advanced numerical model developments
ISSN: 0278-4343
Additional Keywords: SEDIMENT TRANSPORT; MORPHOLOGICAL MODELLING; TURBULENCE MODELLING; SEIMENT INDUCED STRATIFICATION
NORA Subject Terms: Marine Sciences
Date made live: 24 Jun 2011 13:39
URI: http://nora.nerc.ac.uk/id/eprint/13779

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