Mixing Versus Stirring

Emmanuel Villermaux (1)

1 IRPHE - Institut de Recherche sur les Phénomènes Hors Equilibre

Mixing is the operation by which a system evolves under stirring from one state of simplicity-the initial segregation of the constituents-, to another state of simplicity-their complete uniformity-. Between these extremes, patterns emerge, possibly interact, and die sooner of later. This review summarizes the recent developments on the problem of mixing in its lamellar representation. This point of view visualizes a mixture as a set of stretched lamella, or sheets, possibly interacting with each other. It relies on a near-exact formulation of the Fourier equation on a moving substrate and allows to bridge the spatial structure and evolution of the concentration field with its statistical content in an direct way. Within this frame, both the dynamics of the concentration levels in a mixture as a function of the intensity of the stirring motions at the scale of a single lamella, and the interaction rule between adjacent lamella, are described precisely, thus offering a detailed representation of the mixture content, of its structure, and of their evolution in time.

Mots clés: Mixing; stirring; blending; diffusion; transport; statistical mechanisms

Domaines: Sciences de l'ingénieur [physics]; Mécanique [physics.med-ph]

Emmanuel Villermaux. Mixing Versus Stirring. Annual Review of Fluid Mechanics, 2019, 51 (1), pp.245-273. ⟨10.1146/annurev-fluid-010518-040306⟩. ⟨hal-02538304⟩