title: Radial Hele-Shaw flow with suction: fully nonlinear pattern formation.
abstract: We study the development of intricate, fully nonlinear immiscible interfacial patterns in the suction-driven radial Hele-Shaw problem. The complex-shaped, contracting fluid-fluid interface arises when an initially circular blob of more viscous fluid, surrounded by less viscous one, is drawn into an eccentric point sink. We present sophisticated numerical simulations, based on a diffuse interface model, that capture the most prominent interfacial features revealed by existing experimental studies of the problem. The response of the system to changes in the capillary number is investigated, accurately revealing the occurrence of finger competition phenomena, and correctly describing the velocity behavior of both inward- and outward-pointing fingers. For the large-capillary-number regime, a set of complex interfacial features (finger merging, shielding, and pinch-off) whose experimental realization is still not available, are predicted.
authors.affiliation: Department of Mechanical Engineering, National Chiao Tung University, Hsinchu, Taiwan, 30010 Republic of China.
authors.forename: Ching-Yao
authors.initials: CY
authors.lastname: Chen
authors.affiliation: Department of Mechanical Engineering, National Chiao Tung University, Hsinchu, Taiwan, 30010 Republic of China.
authors.forename: Yu-Sheng
authors.initials: YS
authors.lastname: Huang
authors.affiliation: Departamento de Física, Universidade Federal de Pernambuco, Recife, Pernambuco 50670-901 Brazil.
authors.forename: José A
authors.initials: JA
authors.lastname: Miranda