Rayleigh-Taylor Instability, Non-Newtonian Rheology, and Chain Of Bubbles in Polymer Solutions

Michigan Technological University, Houghton MI

Investigators

Abstract

Abstract CTS-0325743 I. Kliakhandler, Michigan Technological University Rayleigh-Tayler Instability, Non-Newtonian Rheology, and Chain of Bubbles in Polymer Solutions The motion of bubbles in a liquid is one of the major fields in hydrodynamics. It was studied already by Leonardo da Vinci, who noticed sinuous movement of rising bubbles, which is relatively easy to observe in long columns. The available body of knowledge and even its language connotation consider bubbles only as a discrete, detached from each other, units. The continuous jet of air in Newtonian liquids produces usual bubbling through Rayleigh-Taylor instability of the jet. In the recent work by PI it was found that in concentrated polymer solutions bubbles may form a qualitatively new structures. The development of Rayleigh-Taylor instability may be arrested by elastic properties of the polymer solutions. As a result, instead of individual bubbles, a long chain of bubbles is formed. The bubbles in the chain are very stable, slowly rising, connected by thin necks; the whole structure is similar to beads, or bubble "sausage"; see figures 1, 2 on the next pages. The rheological properties of polymeric solutions where it is possible to create the chain of bubble are quite interesting and call for their careful study. So far, even the general understanding of this unusual and interesting phenomenon is incomplete. Many basic questions about the chain of bubbles arise; no modeling of the phenomenon has yet been done. The proposed research will be devoted to the study and modeling of chain of bubbles dynamics, and will concentrate on the few main issues; rheology of polymers used in the formation of the chain, experimental elucidation of conditions necessary for the creation of chain of bubbles, analysis of stability of the air jet for various conditions, and strongly nonlinear modeling of the phenomenon.