The stability of a two-fluid rod annular flow

Ferguson Briggs, S. H., Mestel, A. J. and Blyth, M. G. (2025) The stability of a two-fluid rod annular flow. Physical Review Fluids. ISSN 2469-990X (In Press)

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Abstract

Two concentric fluid annuli are enclosed in the gap between an axial rod and an outer cylin- der. Motion is driven both by a pressure gradient and by axial translation of the rod. The linear stability of the flow to axisymmetric and nonaxisymmetric disturbances is studied. New stability regions in parameter space are found for both a stationary and a moving rod. If the fluid viscosi- ties differ, the flow can control the capillary instability at the fluid interface, but may itself be unstable, both at moderate Reynolds number and in the inviscid limit. These flow instabilities may be concentrated either at the interface or the solid boundaries. The interplay between these instabilities depends critically on the problem parameters, and non-axisymmetric modes can be the most unstable. When the outer fluid is more viscous than the inner, complete stabilisation can occur for a sufficiently thick stationary rod, whereas in the absence of the rod, the system is always unstable. Moving the rod can have a stabilising influence either with or without the driving pressure gradient.

Item Type:	Article
Faculty \ School:	Faculty of Science > School of Engineering, Mathematics and Physics
UEA Research Groups:	Faculty of Science > Research Groups > Fluids & Structures
Depositing User:	LivePure Connector
Date Deposited:	11 Feb 2025 18:30
Last Modified:	12 Feb 2025 10:30
URI:	https://ueaeprints.uea.ac.uk/id/eprint/98453
DOI:

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