(296a) Pattern Formation from Interfacial Instabilities in Miscible Viscous Fluids
AIChE Annual Meeting
2017
2017 Annual Meeting
Engineering Sciences and Fundamentals
Interfacial and Nonlinear Flows: Fluid Instabilities
Tuesday, October 31, 2017 - 8:00am to 8:30am
The invasion of one fluid into another of higher viscosity is unstable in a quasi-two dimensional geometry. This viscous-fingering instability typically produces complex patterns that are characterized by repeated branching of the evolving structure, which leads to the common morphologies of fractal or dense-branching growth. However, for two miscible fluids with a high viscosity ratio between the inner and the outer fluid, an entirely different type of pattern formation occurs. Here, structures form that, most remarkably, all expand at nearly the same rate in all directions. This leads to patterns that do not change shape as they develop. This type of growth is called proportionate growth and it has not previously been identified in a physical system despite its common occurrence in the biological world. Such growth relies on a high degree of regulation of the growth rate of widely separated features. We discuss the characteristics of this growth and its relation to the common patterns of fractal, dense-branching and dendritic growth.