Influence of the turbulence closure scheme on the finite-element simulation of the tidal flow around a shallow-water island.

Blaise, Sébastien;White, Laurent;Remacle, Jean-François;Deleersnijder, Eric
(2006) 5th International Workshop On Unstructured Grid Numerical Modeling of Coastal, Shelf and Ocean Flows. — Location: Miami (13.November.2006)

Files

No attached file found for this publication.

Details

Authors
Abstract
The subject of this study is the modelization of the upwelling speed around Rattray Island (Great Barrier Reef, Australia). Field measurements and visual observations show that stable eddies develop in the wake of the island at rising and falling tides. The water turbidity downstream of the island suggests the existence of a strong upwelling that would be responsible for carrying bed sediments up to the sea surface. A three-dimensional finite element model with a simple turbulent closure was recently used to investigate shallow-water eddies in the wake of Rattray Island. However, the upwelling speed predicted by this model was not suffisciently intense to explain the rise of sediments to the sea surface during the life span of the eddies. In this work, we study the influence of a more sophisticated turbulent closure on the upwelling speed. In this aim, a Mellor and Yamada level 2.5 turbulent closure was implemented in the three-dimensional model. Theses results show an increase of the upwelling speed when using this turbulent closure. Another question is the influence of advection of turbulent variables on model results. When averaged over a large horizontal area, it is often assumed that there is little horizontal variations in the turbulent variables, thereby making this term negligible. On smaller scale, this term could be relevant, particularly for complex bathymetries. Simulation were performed on Rattray Island with and without horizontal advection of turbulent variables, in order to estimate its effect.
Affiliations

Citations

  • APA
  • Chicago
  • FWB

Blaise, S., White, L., Remacle, J.-F., & Deleersnijder, E. (2006). Influence of the turbulence closure scheme on the finite-element simulation of the tidal flow around a shallow-water island. 5th International Workshop On Unstructured Grid Numerical Modeling of Coastal, Shelf and Ocean Flows., Miami. https://hdl.handle.net/2078.5/53016