Corrugated interfaces in multiphase core-annular flow

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...

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

Stationary core-annular flow through a horizontal pipe.

A theoretical investigation has been made of core-annular flow: the flow of a high-viscosity liquid core surrounded by a low-viscosity annular liquid layer through a horizontal pipe. Special attention is paid to the question how the buoyancy force on the core, caused by a possible density difference between the core and the annular layer, is counterbalanced. From earlier studies it is known tha...

Stability of Core-Annular Flow with Very Small Viscosity Ratio

It is known that the stability problem for core-annular flow of very viscous crude oil and water is singular, the water annulus appears to be inviscid with boundary layers at the pipe wall and at the interface. In the present paper, this singular problem is treated by the method of matched asymptotic expansions using ∈ = m/Rα as a small parameter. There are two cases of instability correspondin...