Turbulent vortex dipoles in a shallow water layer

Damien Sous (1) , Natalie Bonneton (2) , Joël Sommeria (3)

1 TREFLE - Transferts, écoulements, fluides, énergétique
2 L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux
3 LEGI - Laboratoire des Écoulements Géophysiques et Industriels [Grenoble]

This paper describes an experimental study on turbulent dipolar vortices in a shallow water layer. Dipoles are generated by an impulsive horizontal jet, by which a localized three-dimensional turbulent flow region is created. Dipole emergence is only controlled by the confinement number C=Q‾‾√/H2tinj whereas the jet Reynolds number Re=Q‾‾√/v has no influence in the studied range 50 0002, the flow becomes quasi-two-dimensional and a single vortex dipole emerges in most cases. By qualitative observations and application of particle image velocimetry, the main dipole features have been determined. The shallow water dipoles are characterized by the simultaneous presence of several scales of turbulence: A quasi-two-dimensional main flow at large scale and three-dimensional turbulent motions at small scale. A vertical circulation takes place in the dipole front. A theoretical model is presented and compared to experimental results. The three-dimensional turbulence production occurs mainly in the frontal circulation. A good agreement has been found between the model prediction and the measurements for the velocity evolution.

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Damien Sous, Natalie Bonneton, Joël Sommeria. Turbulent vortex dipoles in a shallow water layer. Physics of Fluids, 2004, 16, pp.2886-2898. ⟨10.1063/1.1762912⟩. ⟨hal-00260753⟩