Thermal Delay of Drop Coalescence

TitleThermal Delay of Drop Coalescence
Publication TypeJournal Article
Year of Publication2017
AuthorsGeri M., Keshavarz B., McKinley G.H, Bush J.WM
JournalJournal of Fluid Mechanics
Start PageR3

We present the results of a combined experimental and theoretical study of drop coalescence in the presence of an initial temperature difference ΔT0 between a drop and a bath of the same liquid. We characterize experimentally the dependence of the residence time before coalescence on ΔT0 for silicone oils with different viscosities. Delayed coalescence arises above a critical temperature difference ΔTc that depends on the fluid viscosity: for ΔT0 > ΔTc, the delay time increases as ΔT02/3 for all liquids examined. This observed dependence is rationalized theoretically through consideration of the thermocapillary flows generated within the drop, the bath and the intervening air layer.