title: Analytical approach to viscous fingering in a cylindrical Hele-Shaw cell.
abstract: We report analytical results for the development of the viscous fingering instability in a cylindrical Hele-Shaw cell of radius a and thickness b. We derive a generalized version of Darcy's law in such cylindrical background, and find it recovers the usual Darcy's law for flow in flat, rectangular cells, with corrections of higher order in b/a. We focus our interest on the influence of the cell's radius of curvature on the instability characteristics. Linear and slightly nonlinear flow regimes are studied through a mode-coupling analysis. Our analytical results reveal that linear growth rates and finger competition are inhibited for an increasingly larger radius of curvature. The absence of tip-splitting events in cylindrical cells is also discussed.
authors.affiliation: Laboratório de Física Teórica e Computacional, Departamento de Física, Universidade Federal de Pernambuco, Recife, PE 50670-901 Brazil. jme@lftc.ufpe.br
authors.forename: José A
authors.initials: JA
authors.lastname: Miranda