Spontaneous Channelization in Draining Thin Film Suspensions

Spontaneous channelization is seen in many everyday draining thin film suspensions, such as yogurt draining down the side of a vertical glass. Furthermore, channelization is also observed as the result of large-scale erosional events including debris flows and mudslides, such as those seen in Montecito, CA in 2018. We hypothesize that there may be some link between these similar phenomena and use small scale thin film flow experiments to attempt to replicate the channelization behavior. Prior research on this topic consists only of one study attributing this behavior to colloidal gelation of particles (Buchanan et al.; 2007); however, channelization is observed in repulsive particles as well, leading us to suspect contribution from another mechanism. We produce channels in the lab using suspensions of quartz particles of varying sizes. Trials including the use of surfactants suggest the importance of the role of capillary action in the channelization process. We propose a phase space of channelization in draining thin film suspensions consisting of the interactions between capillarity and gravity driven flows. We explore the scalability of the capillary process by varying the experimental scale in the lab, with the aim of generalizing the channelization mechanism to explain mudslide behavior as well as commonplace phenomena.

CITATION: Pattern Formation in Draining Thin Film Suspensions M. Buchanan, D. Molenaar, S. de Villiers, and R. M. L. Evans; Langmuir 2007 23 (7), 3732-3736 DOI: 10.1021/la063282a