The research concerns the shape of the interface separating two immiscible liquids. Liquid-liquid flows exhibit phenomena which are totally unexpected from a knowledge of one-fluid flows and form a subject rich in interdisciplinary science. We focuss on physical modeling, analytical and computational techniques to study the stability of various interface shapes, and the appearance of new arrangements from unstable ones. The results touch on industrial applications such as the processing of bicomponent fibers from polymeric melts and lubricated pipelining of viscous crude oil. The overall properties of systems with two fluids are strongly dependent on interface shapes; thus, an understanding of the effects of the component properties on interface shape is of practical importance. This work involves the development of software for 3D transient simulations.
There are a number of algorithms one may pursue for the numerical simulation of interfacial instabilities in parallel shear flows of two fluids with different viscosities. We are further interested in predicting wave bending and breakup, past the point of pinch-off of drops, and we require a method which handles easily the breakup and reformation of interfaces. In this sense, the methods that have been used to predict liquid-liquid jet breakup and subsequent formation of satellite drops are of relevance. Examples include the front tracking (Yeung 1982, Unverdi & Tryggvason 1992) and volume tracking methods (Sussman et al 1994, Kothe et al 1991, Osher and Sethian 1988) which include the volume of fluid scheme. Our paper recently investigated the Volume-of-fluid/Continuous-surface-force scheme.