How vortices mix

Patrice Meunier (1) , Emmanuel Villermaux (1)

1 IRPHE - Institut de Recherche sur les Phénomènes Hors Equilibre

The advection of a passive scalar blob in the deformation field of an axisymmetric vortex is a simple mixing protocol for which the advection-diffusion problem is amenable to a near-exact description. The blob rolls-up in a spiral which ultimately fades away in the diluting medium. The complete transient concentration field in the spiral is accessible from the Fourier equations in a properly chosen frame. The concentration histogram of the scalar wrapped in the spiral presents unexpected singular transient features and its long time properties are discussed in connection with mixtures from the real world.

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

Patrice Meunier, Emmanuel Villermaux. How vortices mix. Journal of Fluid Mechanics, 2003, 476, pp.213 - 222. ⟨hal-00014833⟩