title: Stability of a jet in confined pressure-driven biphasic flows at low reynolds numbers.
abstract: Motivated by its importance for microfluidic applications, we study the stability of jets formed by pressure-driven concentric biphasic flows in cylindrical capillaries. The specificity of this variant of the classical Rayleigh-Plateau instability is the role of the geometry which imposes confinement and Poiseuille flow profiles. We experimentally evidence a transition between situations where the flow takes the form of a jet and regimes where drops are produced. We describe this as the transition from convective to absolute instability, within a simple linear analysis using lubrication theory for flows at low Reynolds number, and reach remarkable agreement with the data.
authors.affiliation: Rhodia Laboratoire du Futur, Unité mixte Rhodia-CNRS, Université Bordeaux I, 178 Avenue du Docteur Schweitzer, 33608 Pessac, France. pierre.guillot@eu.rhodia.com
authors.forename: Pierre
authors.initials: P
authors.lastname: Guillot
authors.forename: Annie
authors.initials: A
authors.lastname: Colin
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Utada
authors.forename: Armand
authors.initials: A
authors.lastname: Ajdari