All Publications
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Crystal aggregates record the pre-eruptive flow field in the volcanic conduit at Kilauea, Hawaii.
Science advances
2020; 6 (49)
Abstract
Developing reliable, quantitative conduit models that capture the physical processes governing eruptions is hindered by our inability to observe conduit flow directly. The closest we get to direct evidence is testimony imprinted on individual crystals or bubbles in the conduit and preserved by quenching during the eruption. For example, small crystal aggregates in products of the 1959 eruption of Kilauea Iki, Hawaii contain overgrown olivines separated by large, hydrodynamically unfavorable angles. The common occurrence of these aggregates calls for a flow mechanism that creates this crystal misorientation. Here, we show that the observed aggregates are the result of exposure to a steady wave field in the conduit through a customized, process-based model at the scale of individual crystals. We use this model to infer quantitative attributes of the flow at the time of aggregate formation; notably, the formation of misoriented aggregates is only reproduced in bidirectional, not unidirectional, conduit flow.
View details for DOI 10.1126/sciadv.abd4850
View details for PubMedID 33277257
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Wettability and capillary effects: Dynamics of pinch-off in unconstricted straight capillary tubes
PHYSICAL REVIEW E
2020; 102 (2)
View details for DOI 10.1103/PhysRevE.102.023109
View details for Web of Science ID 000560673800008
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Wettability and capillary effects: Dynamics of pinch-off in unconstricted straight capillary tubes.
Physical review. E
2020; 102 (2-1): 023109
Abstract
We study the interfacial evolution of immiscible two-phase flow within a capillary tube in the partial wetting regime using direct numerical simulation. We investigate the flow patterns resulting from the displacement of a more viscous fluid by a less viscous one under a wide range of wettability conditions. We find that beyond a wettability dependent critical capillary number, a uniform displacement by a less viscous fluid can transition into a growing finger that eventually breaks up into discrete blobs by a series of pinch-off events for both wetting and nonwetting contact angles. This study validates previous experimental observations of pinch-off for wetting contact angles and extends those to nonwetting contact angles. We find that the blob length increases with the capillary number. We observe that the time between consecutive pinch-off events decreases with the capillary number and is greater for more wetting conditions in the displaced phase. We further show that the blob separation distance as a function of the difference between the inlet velocity and the contact line speed collapses into two monotonically decreasing curves for wetting and nonwetting contact angles. For the phase separation in the form of pinch-off, this work provides a quantitative study of the emerging length and timescales and their dependence on the wettability conditions, capillary effects, and viscous forces.
View details for DOI 10.1103/PhysRevE.102.023109
View details for PubMedID 32942359
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Two-phase multiscale numerical framework for modeling thin films on curved solid surfaces in porous media
JOURNAL OF COMPUTATIONAL PHYSICS
2020; 413
View details for DOI 10.1016/j.jcp.2020.109464
View details for Web of Science ID 000537218200001
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Crystal Fractionation by Crystal-Driven Convection
GEOPHYSICAL RESEARCH LETTERS
2020; 47 (4)
View details for DOI 10.1029/2019GL086784
View details for Web of Science ID 000529120100068
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A locally second order symmetric method for discontinuous solution of Poisson's equation on uniform cartesian grids
COMPUTERS & FLUIDS
2020; 198
View details for DOI 10.1016/j.compfluid.2019.104397
View details for Web of Science ID 000514254000002
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Flow-to-Sliding Transition in Crystal-Bearing Magma
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
2020; 125 (2)
View details for DOI 10.1029/2019JB018549
View details for Web of Science ID 000530895200050
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Direct numerical simulations of viscous suspensions with variably shaped crystals
JOURNAL OF COMPUTATIONAL PHYSICS
2020; 401
View details for DOI 10.1016/j.jcp.2019.109021
View details for Web of Science ID 000501350300034
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Slug Stability in Flaring Geometries and Ramifications for Lava Lake Degassing
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
2018; 123 (12): 10431–48
View details for DOI 10.1029/2018JB016113
View details for Web of Science ID 000455996900006
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Bistability of buoyancy-driven exchange flows in vertical tubes
JOURNAL OF FLUID MECHANICS
2018; 850: 525–50
View details for DOI 10.1017/jfm.2018.382
View details for Web of Science ID 000437766900003
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Direct numerical simulations of gas-solid-liquid interactions in dilute fluids
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
2017; 96: 34–47
View details for DOI 10.1016/j.ijmultiphaseflow.2017.07.008
View details for Web of Science ID 000415909700003
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Topology preserving advection of implicit interfaces on Cartesian grids
JOURNAL OF COMPUTATIONAL PHYSICS
2015; 290: 219–38
View details for DOI 10.1016/j.jcp.2015.02.029
View details for Web of Science ID 000351833400012