Effects of Viscosity Ratio and Surface Wettability on Viscous Fingering Instability in Rectangular Channel

This article reports the effects of viscosity ratio and surface wettability on immiscible viscous �ngering instability in the rectangular channel. A series of numerical investigations perform at various viscosity ratios (VR), i.e., VR ε (0.0009, 0.5), and, walls wettability ( θ ) i.e., θ ε (15°, 150°). The volume of �uid model (VOF) is used to capture the propagation of nger-shaped instability on the �uids interface. We �nd that, at a large viscosity ratio, displacement e�ciency will be more. And, necking formation is observed at low VR and it disappears at large VR. A nger-shaped pattern breaks into two parts at wettability, 15° and above this, it does not break. The wettability shifts from hydrophilic to superhydrophobic then necking disappears. Displacement e�ciency will be more for superhydrophobic wettability. It is observed that instability shifts the left side when wettability shifts from hydrophilic to hydrophilic. The �ndings of this article will be relevant to drug delivery, clinical process, and oil recovery.