Relationship between Fingering Pattern Associated with Gel Formation Reaction and Diffusion at Interface Gel Film

Abstract

In this study, we studied the characteristics of fingering of miscible fluids associated with gel formation between skimmed milk and citric acid solution. Mixing of skimmed milk and citric acid solution leads to form viscoelastic gel, i.e., yogurt, at interface of two fluids. We observed the fingering patterns induced by viscoelastic gel formation at the interface in a Hele-Shaw cell for various concentrations and flow rates. At high citric acid solution concentration, mixing of two fluids is suppressed and unique fingering patterns which are resemble to the sequence of bubbles appear. The distinctive structure like connected bubbles was formed by sequential rupture of gel membrane surrounding bubbles. The thickness of the membrane is modelled mathematically by the competition between the extension of the membrane and the diffusion through it.