HR: 17:45h
AN: H44D-08    [Abstracts]
TI: Quantitative Analysis of the Break-up of Non-Wetting Viscous Fluids in Constricted Capillary Channels
AU: * Beresnev, I
EM: beresnev@iastate.edu
AF: Department of Geological and Atmospheric Sciences, Iowa State University, 253 Science I, Ames, IA 50011-3212, United States
AB: Capillary-pressure analysis for a thread of a viscous fluid surrounded by a wetting phase in a pore leads to an evolution equation describing the temporal dynamics of the fluid/fluid interface. The equation follows from the conservation of mass in the "small-slope" approximation. Its useful applications occur, for example, in petroleum recovery. The nonlinear equation allows inexpensive numerical analysis. For sinusoidally constricted pores, a purely geometric criterion exists that enables or prohibits the viscous-fluid break-up in the neck of the constrictions, which is verified by computational-fluid-dynamics experiments. This geometrically favoring condition sets up capillary-pressure gradients that ensure a continuous outflow of the core fluid from the neck into the "crests" of the profile. Such behavior is indeed observed in the numerical solutions of the evolution equation. For the slopes of the initial configuration close to the fastest-growing wavelength of the linear stability analysis, the break-up is achieved through a quick "collapse" of the interface. As the slope is reduced, the process slows down, and the snap-off is completed through the formation and nonlinear growth of "wavy" disturbances from the initial interface profile, which touch the centerline in several places.
DE: 1847 Modeling
DE: 1849 Numerical approximations and analysis
DE: 3215 Instability analysis
DE: 3653 Fluid flow
SC: Hydrology [H]
MN: 2007 Fall Meeting