Lubricated gravity currents of power-law fluids
| Autor: | Pramoda Kumar, David Kogan, Shahar Zuri, Moshe Gottlieb, Roiy Sayag |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Gravity (chemistry)
Materials science Field (physics) Astrophysics::High Energy Astrophysical Phenomena Flow (psychology) FOS: Physical sciences 02 engineering and technology Condensed Matter - Soft Condensed Matter 01 natural sciences Power law 010305 fluids & plasmas Physics - Geophysics Physics::Fluid Dynamics 0103 physical sciences Newtonian fluid Astrophysics::Galaxy Astrophysics Complex fluid Mechanical Engineering Fluid Dynamics (physics.flu-dyn) Front (oceanography) Physics - Fluid Dynamics Mechanics Physics::Classical Physics 021001 nanoscience & nanotechnology Condensed Matter Physics Geophysics (physics.geo-ph) Gravity current Condensed Matter::Soft Condensed Matter Mechanics of Materials Soft Condensed Matter (cond-mat.soft) 0210 nano-technology |
| Zdroj: | Journal of Fluid Mechanics. 916 |
| ISSN: | 1469-7645 0022-1120 |
| Popis: | The motion of glaciers over their bedrock or drops of fluid along a solid surface can vary dramatically when these substrates are lubricated. We investigate the coupled flow of a gravity current (GC) of a strain-rate softening fluid that is lubricated by a denser, lower-viscosity Newtonian fluid. We present a set of experiments in which such GCs are discharged axisymmetrically and at constant flux over a flat surface. Using imaging techniques, we follow the evolution of the front and thickness field of each fluid. We find that, unlike purely Newtonian lubricated GCs, the fronts of the non-Newtonian and lubricating Newtonian fluids have a power-law time evolution with different exponents. Each of these exponents is similar to that of a non-lubricated GC of the same fluid. Nevertheless, the fronts of our lubricated GCs evolve faster than those of the corresponding non-lubricated GCs owing to larger intercepts. In addition, in contrast with the monotonically declining thickness of non-lubricated GCs, the thickness of the lubricated, non-Newtonian fluid is nearly uniform, and that of the lubricating fluid is non-monotonic with localised spikes. Despite these complex thickness patterns, lubricated GCs remain axisymmetric as long as the flux of the lubricating fluid is sufficiently smaller than that of the non-Newtonian fluid. |
| Databáze: | OpenAIRE |
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