Basal entrainment by Newtonian gravity-driven flows

Bates, Belinda Margaret; Andreini, Nicolas; Ancey, Christophe

doi:10.1063/1.4947242

Cited by 10 publications

(6 citation statements)

References 54 publications

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“…1(a)). In spite of its pervasive appearance on Earth and other moons and planets, this phenomenon of scour still remains as one of the unsolved, classic topics of fluid mechanics (see Lee et al 2016;Aamir and Ahmad 2016;Bates et al 2016), since the times of Leonardo da Vinci and his famous drawings and sketches (Capra 2008).…”

mentioning

confidence: 99%

Temporal evolution of jet induced scour depth in cohesionless granular beds and the phenomenological theory of turbulence

2018

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In this work, we investigate the temporal evolution of the jet-driven scour depth in a pothole lying on a cohesionless granular bed, by using diverse approaches. First, we present new experiments which encompass cases with jet angles ranging from 45 to 90° from the horizontal, several initial water depths, and different particle sizes, supplementing experiments developed recently by the last two authors. In particular, we address relatively-large angles, mostly absent in previous analyses. Our results first confirm the existence of two very different stages in the scour process, essentially overlooked in datasets used to obtain the traditional formulas-developing and developed phases; they then provide unprecedented evidence of the very distinct behavior at 90°, characterized by a step-wise behavior. Second, after revisiting the rationale of a theory our new, and other datasets. Finally, we provide interesting interpretations of the scour process by using the results of the theory.

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confidence: 99%

Temporal evolution of jet induced scour depth in cohesionless granular beds and the phenomenological theory of turbulence

2018

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“…This suggests that the disturbance induced by the surge entering into contact with the erodible layer propagated quickly across that layer. Similarly to what was observed with Newtonian fluids [56], basal entrainment did not involve the propagation of a shock wave separating moving and stationary material, but rather involved an acceleration wave (if we adopt the terminology used in continuum mechanics [64]).…”

Section: Discussionmentioning

confidence: 99%

“…In a previous paper [56] devoted to Newtonian fluids, we investigated the same problem as that presented here. The main difference between viscoplastic and Newtonian fluids is that basal entrainment produces a noticeable increase in the front position in the long run for viscoplastic materials whereas for Newtonian fluids there is little difference between solutions with and without basal entrainment.…”

Section: Numerical Solutionmentioning

confidence: 99%

The dam-break problem for eroding viscoplastic fluids

Bates

Ancey

2017

Journal of Non-Newtonian Fluid Mechanics

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Natural gravity-driven flows can increase in volume by eroding the bed on which they descend. This process is called basal entrainment and is thought to play a key role in the bulk dynamics of geophysical flows. Although its study is difficult using field measurements, basal entrainment is more easily amenable to analysis using laboratory experiments. We studied basal entrainment by conducting dam-break experiments releasing a fixed amount of viscoplastic fluid (a Herschel-Bulkley fluid) on a sloping, erodible bed of fixed depth. Entrainment was observed continuously, far from the sidewalls, using cameras. Bed material was quickly entrained, which led to flow advancement. Although the slope inclination had clear effects on the entrainment mechanisms, as shown by the internal measurements, this did not translate into faster front progression.Instead, the depth and length of the entrainable material were the most important controlling parameters of front velocity, as the surge scoured out the entrainable layer, pushing the entrainable material downstream and following the rigid bed's geometry. Bulk measurements (front position and flow depth profile) were also compared with predictions from lubrication theory.

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“…Total CPU times for the LBM-LES models are presented for grid sizes of 𝑁 𝑛𝑜𝑑𝑒𝑠 ∈ {15, 37.5, 42.2}x10 6 , as this represents the full range of grid sizes used in the present study. The comparison indicates that the LBM-GPU framework reduces total processing time by a factor of approximately 10 3 , when contrasted with the representative total CPU time of the finite-volume NS-LES framework.…”

Section: Computational Performance Of the Lbm-gpu Frameworkmentioning

confidence: 99%

“…4 In the case of turbidity currents, there is the added complexity of the current exchanging particulate material with the boundary through erosion and deposition, resulting in a two-way coupled relationship between the hydrodynamics of the flow and morphodynamics of the channel geometry. 5,6 Direct observation and measurement of turbidity currents in the environment are rare due to the infrequent and destructive nature of the flow.…”

Section: Introductionmentioning

confidence: 99%

Graphics processing unit accelerated lattice Boltzmann method simulations of dilute gravity currents

et al. 2022

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Lattice Boltzmann method models offer a novel framework for the simulation of high Reynolds number dilute gravity currents. The numerical algorithm is well suited to acceleration via implementation on massively parallel computer architectures. Here, we present two lattice Boltzmann method models of lock-exchange dilute gravity currents in which the largest turbulent length scales are directly resolved. The three-dimensional simulations are accelerated by exporting computations to a graphics processing unit and are validated against experiments and high-resolution simulations for Reynolds numbers up to 30 000. The lattice Boltzmann method models achieve equivalent accuracy to conventional large-eddy simulation models in the prediction of key flow properties. A conservative analysis of computational performance relative to conventional methods indicates that the presented framework reduces simulation times by two orders of magnitude. Therefore, it can be used as a foundation for the development of depth-resolving models that capture more of the complexity of environmental gravity currents.

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Basal entrainment by Newtonian gravity-driven flows

Abstract: Investigation on subsonic to supersonic flow around a sphere at low Reynolds number of between 50 and 300 by direct numerical simulation

Cited by 10 publications

References 54 publications

Temporal evolution of jet induced scour depth in cohesionless granular beds and the phenomenological theory of turbulence

Temporal evolution of jet induced scour depth in cohesionless granular beds and the phenomenological theory of turbulence

The dam-break problem for eroding viscoplastic fluids

Graphics processing unit accelerated lattice Boltzmann method simulations of dilute gravity currents

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