Thermal delay of drop coalescence. (8th November 2017)

• Record Type: Journal Article
• Authors: Geri, Michela; Keshavarz, Bavand; McKinley, Gareth H.; Bush, John W. M.
• Is Part Of: Journal of fluid mechanics. Volume 833(2017)
• Publication Date: 2017-11-08
• Subjects: breakup/coalescence, -- Marangoni convection, -- thermocapillarity; Fluid mechanics -- Periodicals; 532.005
• DOI: 10.1017/jfm.2017.686
• Languages: English
• ISSNs: 0022-1120

Abstract

Abstract : We present the results of a combined experimental and theoretical study of drop coalescence in the presence of an initial temperature difference $\unicode[STIX]{x0394}T_{0}$ between a drop and a bath of the same liquid. We characterize experimentally the dependence of the residence time before coalescence on $\unicode[STIX]{x0394}T_{0}$ for silicone oils with different viscosities. Delayed coalescence arises above a critical temperature difference $\unicode[STIX]{x0394}T_{c}$ that depends on the fluid viscosity: for $\unicode[STIX]{x0394}T_{0}>\unicode[STIX]{x0394}T_{c}$, the delay time increases as $\unicode[STIX]{x0394}T_{0}^{2/3}$ 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.