title: Gravity-driven instability in a spherical Hele-Shaw cell.
abstract: A pair of concentric spheres separated by a small gap form a spherical Hele-Shaw cell. In this cell an interfacial instability arises when two immiscible fluids flow. We derive the equation of motion for the interface perturbation amplitudes, including both pressure and gravity drivings, using a mode coupling approach. Linear stability analysis shows that mode growth rates depend upon interface perimeter and gravitational force. Mode coupling analysis reveals the formation of fingering structures presenting a tendency toward finger tip-sharpening.
authors: Laboratório de Física Teórica e Computacional, Departamento de Física, Universidade Federal de Pernambuco, Recife, PE 50670-901 Brazil.
authors: J A
authors: JA
authors: Miranda
authors: F
authors: F
authors: Parisio
authors: F
authors: F
authors: Moraes
authors: M
authors: M
authors: Widom