Various interface instability phenomena of active fluid in Hele-Shaw cell

Abstract

The interface between stearyl trimethylammonium (STAC) and palmitic acid (PA) vibrates spontaneously because of chemical nonequilibrium. This dynamic motion of the interface is often referred as “blebbing,” and explained as the gel formation and the change in its thickness with time. In this paper, the influence of gel formation by the chemical reaction and blebbing at the interface on the displacement process has been investigated in Hele-Shaw cell. Gel formation at the interface stabilizes the fingering with an increase in the injection rate, in contrast to normal viscos fingering associated with the viscosity ratio. In injected aqueous phase, unique residual oil blobs which grow from the web-like structure at the interface was found. This oil residual process was similar to spinodal water repellent. When injecting the oil phase into the water phase, blebbing was observed at the interface. This blebbing causes a decrease in the replacement area.