Splitting morphology of low-viscous finger at different junctions of microchannels

Abstract

This paper reports the splitting morphology of low-viscous fingers in the microchannels that are associated with flat T-shaped, curved T-shaped, and Y-shaped junctions. The numerical simulations are based on the finite volume approach and the volume of the fluid model. In this study, microchannels are filled with silicon oil. Perfluorodecalin is used to displace silicon oil from the microchannels. Due to viscosity differences, the low-viscous finger (LVF)-shaped instability evolves at the interface of fluids. A single LVF propagates in the parent channel, and at the junction, it splits into two identical LVFs. It is noted that the splitting morphology of LVF depends upon the shape of the junction and its wettability. Therefore, there are three different junctions, i.e. flat T-shaped, curved T-shaped, and Y-shaped, with three different wettability conditions [Formula: see text], i.e. hydrophilic ([Formula: see text]), hydrophobic ([Formula: see text]), and superhydrophobic ([Formula: see text]) are used for numerical investigation. It is found that a LVF splits symmetrically at all three different junctions but tips of LVFs are found to be convex in superhydrophobic conditions. The LVFs-shaped are curved in the limbs of curved T-shaped microchannel and straight in the limbs of flat T-shaped and Y-shaped microchannels. The findings of this paper may be used in lung biomechanics, respiratory diseases, biochemical testing, and many more.