Numerical treatment of the steady flow of a liquid compound jet

A numerical treatment of the outflow of a two-layer laminar jet into a non-viscous continuous phase is performed. The dispersed phases (i.e. the central core and the concentric layer) are immiscible, incompressible and Newtonian fluids. The method of solution allows for the simultaneous determination of the shape of both interfaces, as well as of the corresponding velocity profiles. The equations of motion of both phases are obtained in a boundary layer approximation. The pressure jump in the radial direction, owing to forces of interfacial tension, is taken into account. Also studied is how the initial velocity profiles at the nozzle exit and some dimensionless parameters affect the interaction between the primary and secondary flow. Numerical results agree qualitatively with some experimental evidence. The approach can also be employed to predict the flow within a viscous continuous phase.