Year: 2009
Type: article
Abstract: We investigate experimentally the mixing dynamics of a blob of dye in a channel flow with a finite stirring region undergoing chaotic advection. We study the homogenization of dye in two variants of an eggbeater stirring protocol that differ in the extent of their mixing region. In the first case, the mixing region is separated from the sidewalls of the channel, while in the second it extends to the walls. For the first case, we observe the onset of a permanent concentration pattern that repeats over time with decaying intensity. A quantitative analysis of the concentration field of dye confirms the convergence to a self-similar pattern, akin to the strange eigenmodes previously observed in closed flows. We model this phenomenon using an idealized map, where an analysis of the mixing dynamics explains the convergence to an eigenmode. In contrast, for the second case the presence of no-slip walls and separation points on the frontier of the mixing region leads to non-self-similar mixing dynamics.
Source: Physics of Fluids
DOI: 10.1063/1.3080680
Authors: E. Gouillart, O. Dauchot, J.-L. Thiffeault, S. Roux
Institutions: Centre National de la Recherche Scientifique, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Service de Physique de l'État Condensé, CEA Paris-Saclay, Surface du Verre et Interfaces, University of Wisconsin–Madison, École Normale Supérieure Paris-Saclay, Université Pierre-et-Marie-Curie
Language: English
Subfield: Computational Mechanics
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2072880962