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Accueil > Équipes > Equipe MEIGE : Modélisation, Expériences et Instrumentation pour la Géophysique et l’Environnement > Diffusion scientifique > Séminaires internes

Dynamics of gravity currents on concave and convex slopes

Ana-Marija Duranec, 03/07/2014

This presentation is dealing with dynamics of gravity currents on a slope and better understanding the instabilities appearing and leading to the turbulent state of the
ow, such as Görtler vortices and Kelvin-Helmholtz vortices. Four different simulations were performed, using the LES (Large Eddy Simulation), for two different slopes - concave and convex. For the concave slope two simulations were performed coarse mesh and fine mesh. The differences were small enough so for the convex case only coarse mesh was used - both for small and enlarged domain. Flow streamline passing through one of the Görtler vortices was extracted for both concave and convex case. Two streamlines were similar in a way that first part of the flow was convex while further in the domain streamlines tended to concavity. For that reason further analysis were performed just for the convex case. It was observed that vortices were more visible in the larger domain than in the smaller, so analysis were made for large domain. Several parameters were investigated, such as velocity, density, Görtler number, momentum thickness, turbulent
uxes etc. Görtler and Kelvin - Helmholtz instabilities were observed in the flow but in different positions - Görtler instabilities in the convex part of the flow and Kelvin - Helmholtz instabilities in the concave part of the flow.