We present a comprehensive computational physics-based study of the influence of surface wettability on the displacement behavior of a droplet in a three-dimensional bifurcating channel. Various surface wettability configurations for the daughter branches are considered to gain insight into the wettability–capillarity interaction. Also, the influence of initial droplet size on the splitting dynamics for different wettability configurations is investigated. Time evolution of the droplet displacement behavior in the bifurcating channel is discussed for different physicochemical parameters including capillary number and wettability. Three distinct flow regimes are identified as the droplet interacts with the bifurcating tip of the channel, namely, splitting, nonsplitting, and oscillating regimes. Furthermore, the occurrence of Rayleigh–Plateau instability in different wettability scenarios is discussed. Additionally, the intricacies associated with the droplet dynamics are elucidated through the temporal evolution of the droplet surface area and mass outflow of the continuous phase. A flow regime map based on the capillary number and wettability contrast of the daughter branches is proposed for a comprehensive description of the droplet dynamics.

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Present study numerically investigates the merging dynamics of two identical dispersed droplets within a Y-shaped bifurcating channel of rectangular crosssection. A finite element method based solver is adopted to analyze the flow dynamics within the bifurcating channel for different wall wettability conditions, initial size of the dispersed droplets and for a fixed Capillary number. The merging dynamics is described with the help of morpho-dynamic evolution along with the temporal evolution of wetted area of the droplets. It reveals that the daughter droplet generated from the mating of identical parent droplets at the bifurcating tip has the affinity to stick at the junction for hydrophilic and neutral wettability configurations of the walls, thus generating longer size droplet. On the contrary, for hydrophobic wettability of the walls, the parent droplets merge to each other bypassing the bifurcating junction while mating and subsequently entrapping of droplets takes place within the daughter droplet. Moreover, the influence of wall wettability is insignificant when the initial sizes of the parent droplets are smaller.

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