Convective/absolute instability in miscible core-annular flow. Part 1: Experiments

Non-Axisymmetric Instability of Core-Annular Flow

Stability of core-annular flow of water and oil in a vertical circular pipe is studied with respect to nonaxisymmetric disturbances. Results show that when the oil core is thin, the flow is most unstable to the asymmetric sinuous mode of disturbance, and the core moves in the form of corkscrew waves as observed in experiments. The asymmetric mode of disturbance is the most dangerous mode for qu...

Forced instability of core-annular flow in capillary constrictions

Lubricated Pipelining: Stability of Core-Annular Flow. Part 2

In this paper, we study the linearized stability of three symmetric arrangements of two liquids in core-annular Poiseuille flow in round pipes. Deferring to one important application, we say oil and water when we mean more viscous and less viscous liquids. The three arrangements are (i) oil is in the core and water on the wall, (ii) water is in the core and oil is outside and (iii) three layers...

Corrugated interfaces in multiphase core-annular flow

Microfluidic devices can be used to produce highly controlled and monodisperse double or multiple emulsions. The presence of inner drops inside a jet of the middle phase introduces deformations in the jet, which leads to breakup into monodisperse double emulsions. However, the ability to generate double emulsions can be compromised when the interfacial tension between the middle and outer phase...

Instability Analysis of Miscible Displacements in Homogeneous Porous Media