Non-Isothermal Buoyancy Driven Exchange Flow of Miscible Fluids in Inclined Pipes



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This thesis studies non-isothermal buoyancy-driven exchange flow of two miscible Newtonian fluids in an inclined pipe experimentally. The cold heavy fluid is released into the hot light one in an adiabatic small-aspect-ratio pipe in the Boussinesq limit. The maximal rate of interpenetration of the fluids in non-isothermal case is similar to the isothermal limit, maximal rate occurs at an intermediate angle. There has also been observed a novel asymmetric behavior in the flow never observed before in the isothermal limit in which the cold finger appears to advance faster than the hot one. Backed by meticulously-designed supplementary experiments, this asymmetric behavior is hypothetically associated with the wall contact and the formation of a warm less-viscous film of the fluid lubricating the cold more-viscous finger along the pipe. The asymmetric behavior of the flow is finally quantified over the full range of non-isothermal experiments carried.



Non-isothermal, Buoyancy-driven flow, Boussinesq limit, Asymmetric, Viscous film