Mixing across a density interface in a Taylor-Couette flow

Estelle Guyez (1) , Jan-Bert Flór (1) , Emil J. Hopfinger (1)

1 LEGI - Laboratoire des Écoulements Géophysiques et Industriels [Grenoble]

In this paper we report on an experimental investigation of the interfacial mixing by Taylor vortices. Using the LIF method the evolution of the density field is followed in time for a range of buoyancy frequencies and Reynolds numbers. It is found that the buoyancy flux, represented as a function of the buoyancy gradient, shows a similar tendency as the mixing in isotropic turbulent flows. New is the increase in buoyancy flux for very large buoyancy gradients, predicted by the model of Balmforth et al. (1998). Since shear instabilities are unlikely to occur, other changes in the mixing processes should be responsible. In addition a spread in the maximum mixing efficiency is found, which is dependent on Reynolds number. The origins of this Reynolds number dependence, as well as the application of the mixing results to Langmuir Circulation in the ocean thermocline are discussed.

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

Estelle Guyez, Jan-Bert Flór, Emil J. Hopfinger. Mixing across a density interface in a Taylor-Couette flow. ISSF international Symposium on Stratified Fluid, Dec 2006, Perth, Australia. ⟨hal-00207211⟩