DYNAMIQUE INSTATIONNAIRE DE L’ECOULEMENT A L’AVAL D’UNE RIDE
Résumé
Mean flow over a dune was investigated at Reynolds number, based on dune hight, between 125 and 700. At Reynolds 600,details study of the instationnary flow were conducted. Measurements with two component Particules Image Velocimetry andflow visualization, are performed to acquire and obtain a detailed knowledge of the flow over a single fixed dune. In this paper,vortices structures evolution is depicted from the beginning of their formation near the trough dune til their vanishing above theleeside of the dune. Results exhibit an important evolution of opposite sign of instantanous vorticity and diminution in lengh ofthe recirculation region.
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