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arXiv · 2101.00293

Coalescence and spreading of drops on liquid pools

Varun Kulkarni·Venkata Yashasvi Lolla·Suhas Rao Tamvada·Nikhil Shirdade·Sushant Anand
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Abstract

Oil spills have posed a serious threat to our marine and ecological environment in recent times. Containment of spills proliferating via small drops merging with oceans/seas is especially difficult since their mitigation is closely linked to the coalescence dependent spreading. This inter-connectivity and its dependence on the physical properties of the drop has not been explored until now. Furthermore, pinch-off behavior and scaling laws for such three-phase systems have not been reported. To this end, we investigate the problem of gentle deposition of a single drop of oil on a pool of water, representative of an oil spill scenario. Methodical study of 11 different n-alkanes, polymers and hydrocarbons with varying viscosity and initial spreading coefficients is conducted. Regime map, scaling laws for deformation features and spreading behavior are established. The existence of a previously undocumented regime of delayed coalescence is revealed. It is seen that the inertia-visco-capillary (I-V-C) scale collapses all experimental drop deformation data on a single line while the early stage spreading is found to be either oscillatory or asymptotically reaching a constant value, depending on the viscosity of the oil drop unlike the well reported monotonic, power law late-time spreading behavior. These findings are equally applicable to applications like emulsions and enhanced oil recovery.

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Varun Kulkarni, Venkata Yashasvi Lolla, Suhas Rao Tamvada, Nikhil Shirdade, Sushant Anand. 2021-01-01. Coalescence and spreading of drops on liquid pools. https://doi.org/10.1016/j.jcis.2020.10.089

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