Multiphase multilayer viscoplastic displacement flows: Controlling interfacial patterns

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The displacement of one fluid by another fluid of usually different properties occurs in a variety of natural and industrial applications. The hard-to-achieve objective is typically to completely remove the in-situ displaced fluid, via the imposed displacing fluid, while the fluid-fluid interface participates actively in the flow dynamics. Relevant to this fundamentally-challenging fluid mechanics problem, our research program's long-term vision revolves around developing advanced flow models/simulations and novel experiments, to improve Canadian industrial processes dealing with displacement flows, whose complex, multiphase, multilayer, interfacial and non-Newtonian nature are critical. Examples include displacement flows in removal/cleaning processes in the plug and abandonment of oil&gas wells, as well as various processes in aluminum production, cleaning/removal and decontamination, and injection molding. The fluids and materials used in these and similar industrial processes frequently exhibit non-Newtonian viscoplastic properties, for which the rheology becomes even more complex when thixotropy and viscoelastic transient responses are considered. These complexities, along with highly non-linear and hard-to-predict interfacial behaviour, make it extremely hard to control these complex interfacial displacement flows. In this context, our vision is to develop ground-breaking methods and strategies to effectively control the advancement and penetration of multiphase, multilayer viscoplastic fluids into one another. This can be realized, for example, via controlling/manipulating the spatiotemporal interface evolution and hindering/triggering interfacial phenomena, to achieve desired displacement flow patterns/regimes, according to our design and needs. This in return enables us to precisely predict/design complex displacement behaviours in a broad range of industrial processes, and reduce concomitant negative impacts of unpredictability/uncontrollability of these flows. In this framework, our specific short-term objectives are to propose transformative controlling displacement strategies, via the analysis of (i) immiscible viscoplastic displacements in rotating pipes, (ii) displacements in flow geometries with superhydrophobic walls, and (iii) thixo-elasto-visco-plastic displacement flows. These fascinating research topics proposed are investigated through novel complex fluid experiments (e.g. laser/camera/ultrasound imaging), rigorous semi-analytical mathematical models (lubrication, asymptotic and stability analysis models), and advanced computational fluid dynamics methods relying on open-source codes. Through engaging both graduate and undergraduate students, these highly qualified personnel trained in our research program experience a unique educational environment, designed for mathematical and experimental modeling of complex flows, i.e. a research area for which the demand for expertise and skills is increasing.