English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Topological chaos has emerged as a powerful tool to investigate fluid mixing.While this theory can guarantee a lower bound on the stretching rate of certainmaterial lines, it does not indicate what fraction of the fluid actuallyparticipates in this minimally mandated mixing. Indeed, the area in whicheffective mixing takes place depends on physical parameters such as theReynolds number. To help clarify this dependency, we numerically simulate theeffects of a batch stirring device on a 2D incompressible Newtonian fluid inthe laminar regime. In particular, we calculate the finite time Lyapunovexponent (FTLE) field for three different stirring protocols, one topologicallycomplex (pseudo-Anosov) and two simple (finite-order), over a range ofviscosities. After extracting appropriate measures indicative of both theamount of mixing and the area of effective mixing from the FTLE field, we see aclearly defined Reynolds number range in which the relative efficacy of thepseudo-Anosov protocol over the finite-order protocols justifies theapplication of topological chaos. More unexpectedly, we see that while themeasures of effective mixing area increase with increasing Reynolds number forthe finite-order protocols, they actually exhibit non-monotonic behavior forthe pseudo-Anosov protocol.

Reynolds number effects on mixing due to topological chaos