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Accueil > Actualités > Séminaires > Séminaires 2009

Mardi 13 janvier à 11:00 - Amphi Craya

Eletta Negretti

Titre/Title :
Interfacial waves and entrainment in two-layer stratified flows over topography

Contact :
Jan-Bert Flor

Résumé/Abstract :

Two-layer stratified flows are commonly observed in geophysical and environmental contexts. At the interface between the two layers, both velocity shear and buoyancy interplay, resulting in various modes of instability. Results from an experimental study with high Reynolds numbers are presented, investigating the nature of an oscillating barotropic forcing and its effect on interfacial waves and on entrainment in two-layer baroclinic exchange flows over an underwater sill. The effect of locally enhanced bottom roughness has also been studied employing three bottom roughness configurations, a smooth bed and two artificially roughened beds, with sparse and dense roughness elements, respectively. The onset and growth of small scale instabilities, such as Kelvin-Helmholtz and Holmboe instabilities, has also been studied by means of temporal linear stability analysis, analyzing the effect of a mild bottom slope on the stability of the interface.

Finally, some preliminary results on the ongoing research relative to stratified turbulence will be presented.