The surprising relevance of a continuum description to granular clusters

Louge, Michel Y.

doi:10.1017/jfm.2013.650

Cited by 7 publications

(7 citation statements)

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“…The IR is an important part of our classification system that may be helpful in explaining the longevity and mobility of PSAs (Köhler et al, ), by significantly increasing the mass flux into the powder cloud and increasing the turbulent kinetic energy. New modeling concepts must be developed, since velocity and density variations (Sovilla et al, ) may not be described with standard depth‐averaged numerical approaches, though there can be good agreement (Louge, ). Future work can build up on the descriptive terminology developed here and connect rheological properties of snow to the expression of flow regimes by combining our results with the wide field of cohesive and noncohesive granular flows.…”

Section: Discussionmentioning

confidence: 99%

GEODAR Data and the Flow Regimes of Snow Avalanches

Köhler

McElwaine

Sovilla³

2018

JGR Earth Surface

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GEOphysical flow dynamics using pulsed Doppler radAR (GEODAR), a custom radar system, images avalanches over the entire slope with high spatial and temporal resolution at the experimental test site Vallée de la Sionne in Switzerland. Between winter seasons 2009/2010 and 2014/2015, data have been acquired from 77 avalanches. These data sets describe a wide variety of avalanches, which we classify in terms of seven flow regimes and combinations thereof. These flow regimes expand on previous classifications, with four identifiable dense flow regimes (where interaction between granules and with the flow bed dominates dynamics) and two different dilute flow regimes (where interaction between snow particles and the air becomes dominant). There is a further regime identified where snow balls simply roll down the mountain. A cold dense regime and a warm shear regime behave like noncohesive granular flows with velocity shear throughout the flow. A sliding slab regime and a warm plug regime occur when cohesion dominates and causes the flow units to act as solid‐like objects sliding on a thin shear zone. An intermittent regime connects the cold dense regime with the suspension regime and is characterized by highly fluctuating density and surging activity. GEODAR enables localization of these flow regimes and transitions between them in time and space. We discuss flow regime transitions in terms of snow properties, topography, speed, and size of the avalanches. This paper also serves as a reference for the data set which is made publicly available and should prove to be an invaluable resource for the development of physically based avalanche models.

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Section: Discussionmentioning

confidence: 99%

GEODAR Data and the Flow Regimes of Snow Avalanches

Köhler

McElwaine

Sovilla³

2018

JGR Earth Surface

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“…L coll (f (1) , g (2) ), (27) where the argument of L coll has changed to account for the assumption eq. ( 17).…”

Section: Ddft Derivationsmentioning

confidence: 99%

“…The moments eqs. (26) and (27) can be constructed analytically by using standard results for moments of Gaussians with mean µ and variance ς:…”

Section: A Moments Of the Collision Operatormentioning

confidence: 99%

“…Such constitutive equations, in the dilute flow regime, are usually obtained by invoking the kinetic-collisional theory [30]. The disadvantages of such constitutive equations lie mainly in what is believed to be its inability to treat the meso-scale: issues such as cluster formation (and breakage), for instance, have been discussed at large [27], and attempts to solve those issues have been proposed (e.g., by adjusting the Navier-Stokes equations [27,35]).…”

Section: Introductionmentioning

confidence: 99%

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Modelling inelastic granular media using Dynamical Density Functional Theory

Goddard,

Hurst,

Ocone

2020

Preprint

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We construct a new mesoscopic model for granular media using Dynamical Density Functional Theory (DDFT). The model includes both a collision operator to incorporate inelasticity and the Helmholtz free energy functional to account for external potentials, interparticle interactions and volume exclusion. We use statistical data from event-driven microscopic simulations to determine the parameters not given analytically by the closure relations used to derive the DDFT. We numerically demonstrate the crucial effects of each term in the DDFT, and the importance of including an accurately parametrised pair correlation function.

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“…Such constitutive equations, in the dilute flow regime are usually obtained by invoking the kinetic-collisional theory [34]. The disadvantages of such constitutive equations lie mainly in what is believed to be its inability to treat the meso-scale: issues such as cluster formation (and breakage), for instance, have been discussed at large [31], and attempts to solve those issues have been proposed (e.g., by adjusting the Navier-Stokes equations [31,41]).…”

mentioning

confidence: 99%

Modelling inelastic Granular Media Using Dynamical Density Functional Theory

2021

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We construct a new mesoscopic model for granular media using Dynamical Density Functional Theory (DDFT). The model includes both a collision operator to incorporate inelasticity and the Helmholtz free energy functional to account for external potentials, interparticle interactions and volume exclusion. We use statistical data from event-driven microscopic simulations to determine the parameters not given analytically by the closure relations used to derive the DDFT. We numerically demonstrate the crucial effects of each term and approximations in the DDFT, and the importance of including an accurately parametrised pair correlation function.

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The surprising relevance of a continuum description to granular clusters

Cited by 7 publications

References 34 publications

GEODAR Data and the Flow Regimes of Snow Avalanches

GEODAR Data and the Flow Regimes of Snow Avalanches

Modelling inelastic granular media using Dynamical Density Functional Theory

Modelling inelastic Granular Media Using Dynamical Density Functional Theory

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