Control of a purely-elastic symmetry-breaking flow instability in cross-slot geometries



Davoodi, M, Domingues, AF ORCID: 0000-0003-2071-6738 and Poole, RJ ORCID: 0000-0001-6686-4301
(2019) Control of a purely-elastic symmetry-breaking flow instability in cross-slot geometries. Journal of Fluid Mechanics, 881. 1123 - 1157.

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Abstract

The cross-slot stagnation point flow is one of the benchmark problems in non-Newtonian fluid mechanics as it allows large strains to develop and can therefore be used for extensional rheometry measurements or, once instability arises, as a mixing device. In such a flow, beyond a critical value for which the ratio of elastic force to viscous force is high enough, elasticity can break symmetry even in the absence of significant inertial forces (i.e. creeping flow), which is an unwanted phenomenon if the device is to be used as a rheometer but beneficial from a mixing perspective. In this work, a passive control mechanism is introduced to the cross-slot by adding a cylinder at the geometric centre to replace the ‘free’ stagnation point with ‘pinned’ stagnation points at the surface of the cylinder. In the current modified geometry, effects of the blockage ratio (the ratio of the diameter of the cylinder to the width of the channel), the Weissenberg number (the ratio of elastic forces to viscous forces) and extensibility parameters (

Item Type: Article
Depositing User: Symplectic Admin
Date Deposited: 01 Oct 2019 13:05
Last Modified: 18 Sep 2021 01:10
DOI: 10.1017/jfm.2019.781
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3056550