Wettability controls slow immiscible displacement through local interfacial instabilities

Jung, Michael, Brinkmann, Martin, Seemann, Ralf, Hiller, Thomas, Sanchez de La Lama, Marta and Herminghaus, Stephan (2016) Wettability controls slow immiscible displacement through local interfacial instabilities. Physical Review Fluids, 1 (7). ISSN 2469-990X

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Abstract

Immiscible fluid displacement with average front velocities in the capillary-dominated regime is studied in a transparent Hele-Shaw cell with cylindrical posts. Employing various combinations of fluids and wall materials allows us to cover a range of advancing contact angles 46∘≤θa≤180∘ of the invading fluid in our experiments. In parallel, we study the displacement process in particle-based simulations that account for wall wettability. Considering the same arrangement of posts in experiments and simulation, we find a consistent crossover between stable interfacial displacement at θa≲80∘ and capillary fingering at high contact angles θa≳120∘. The position of the crossover is quantified through the evolution of the interface length and the final saturation of the displaced fluid. A statistical analysis of the local displacement processes demonstrates that the shape evolution of the fluid front is governed by local instabilities as proposed by Cieplak and Robbins for a quasistatic interfacial displacement [Cieplak and Robbins, Phys. Rev. Lett. 60, 2042 (1988)]. The regime of stable front advances coincides with a corresponding region of contact angles where cooperative interfacial instabilities prevail. Capillary fingering, however, is observed only for large θa, where noncooperative instabilities dominate the invasion process.

Item Type:	Article
Uncontrolled Keywords:	displacement of immiscible fluids, imbibition and injection, interfacial phenomena, multiphase flows
Subjects:	F300 Physics
Department:	Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User:	Paul Burns
Date Deposited:	23 Oct 2019 16:57
Last Modified:	23 Oct 2019 16:57
URI:	http://nrl.northumbria.ac.uk/id/eprint/41218

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