title: Symmetric drop coalescence on an under-liquid substrate.
abstract: We have derived a modified one-dimensional lubrication equation to describe the early coalescence behavior of a symmetric sessile drop coalescence for under-liquid substrates, which takes into account the viscosities of both the drop and the surrounding medium. We found a time scale, which governs the process, and there exists a crossover time between the universal scaling of the bridge height growth h^{*}∼t^{*} (valid for both under-liquid and air) and a much slower bridge growth h^{*}∼t^{*}^{0.24} occurring at a later time. It is also found that the drop coalescence bridge profile has a self-similarity, which breaks up much earlier for under-liquid substrates as opposed to symmetric coalescence in air.
authors.affiliation: Micro and Nano-scale Transport Laboratory, Department of Mechanical Engineering, Lassonde School of Engineering, York University, Toronto, Ontario, Canada M3J 1P3.
authors.forename: Surjyasish
authors.initials: S
authors.lastname: Mitra
authors.affiliation: Micro and Nano-scale Transport Laboratory, Department of Mechanical Engineering, Lassonde School of Engineering, York University, Toronto, Ontario, Canada M3J 1P3.
authors.forename: Sushanta K
authors.initials: SK
authors.lastname: Mitra