Please use this identifier to cite or link to this item: http://hdl.handle.net/2445/97483
Title: Experimental study of stable imbibition displacements in a model open fracture. I. Local avalanche dynamics
Author: Clotet i Fons, Xavier
Ortín, Jordi, 1959-
Santucci, Stéphane
Keywords: Dinàmica de fluids
Calci
Capil·laritat
Silicones
Viscositat
Velocitat
Fluid dynamics
Calcium
Capillarity
Silicones
Viscosity
Speed
Issue Date: 28-Jan-2016
Publisher: American Physical Society
Abstract: We report the results of an experimental investigation of the spatiotemporal dynamics of stable imbibition fronts in a disordered medium, in the regime of capillary disorder, for a wide range of experimental conditions. We have used silicone oils of various viscosities μ and nearly identical oil-air surface tension and forced them to slowly invade a model open fracture at different constant flow rates v. In this first part of the study we have focused on the local dynamics at a scale below the size of the quenched disorder. Changing μ and v independently, we have found that the dynamics is not simply controlled by the capillary number Ca ∼ μv. Specifically, we have found that the wide statistical distributions of local front velocities, and their large spatial correlations along the front, are indeed controlled by the capillary number Ca. However, local velocities exhibit also very large temporal correlations, and these correlations depend more strongly on the mean imposed velocity v than on the viscosity μ of the invading fluid. Correlations between local velocities lead to a burstlike dynamics. Avalanches, defined as clusters of large local velocities, follow power-law distributions both in size and duration with exponential cutoffs that diverge as Ca → 0, the pinning-depinning transition of stable imbibition displacements. Large data sets have led to reliable statistics, from which we have derived accurate values of critical exponents of the relevant power-law distributions. We have investigated also the dependence of their cutoffs on μ and v and related them to the autocorrelations of local velocities in space and time.
Note: Reproducció del document publicat a: http://dx.doi.org/10.1103/PhysRevE.93.012149
It is part of: Physical Review E, 2016, vol. 93, num. 1, p. 012149-1-012149-13
Related resource: http://dx.doi.org/10.1103/PhysRevE.93.012149
URI: http://hdl.handle.net/2445/97483
ISSN: 1539-3755
Appears in Collections:Articles publicats en revistes (Física Quàntica i Astrofísica)

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