Buoyant miscible displacement flows of Newtonian and non-Newtonian fluids : stationary and oscillating geometries
|Advisor:||Larachi, Faïcal; Taghavi, Seyed Mohammad|
|Abstract:||This thesis aims to investigate buoyant displacement flows of miscible fluids in a long, vertical stationary pipe or a moving pipe. For the case of the moving geometry, the pipe oscillates like an inverted pendulum with a small maximum frequency, i.e.ˆf= 0.2(Hz) and a small maximum oscillation amplitude, i.e. 15 (◦) with respect to the pipe axis. The displacement flows occur at the high Péclet number and small Atwood numbers. The focus is on the type of fluids and geometries (stationary or moving pipe). Detailed experimental approaches are employed in an integrated fashion. The density configuration in this thesis is the density unstable. The main part of the current work is concentrated on displacement flows of iso-viscous Newtonian fluids. We also study the yield stress displacement flow in a long vertical pipe. For iso-viscous Newtonian displacement flow in a stationary pipe, we uncover the stabilizing effect of the mean imposed flow and report the existence of two main flow regimes at long times introduced as a stable displacement flow and an unstable displacement flow. The transition between these two regimes occurs at a critical modified Reynolds number (Ret|
|Document Type:||Thèse de doctorat|
|Open Access Date:||18 October 2019|
|Collection:||Thèses et mémoires|
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