Steady state rheology of homogeneous and inhomogeneous cohesive granular materials

Shi, Hao; Roy, Sudeshna; Weinhart, Thomas; Magnanimo, Vanessa; Luding, Stefan

doi:10.1007/s10035-019-0968-5

Cited by 27 publications

(15 citation statements)

References 79 publications

(139 reference statements)

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“…Regime maps for cohesive‐particle flows have been a mainstay in industry for the prediction of various unit operations 10,13–15,26,62,64–70 . The generality (or lack thereof) of a given regime map depends on what quantities are being plotted.…”

Section: Discussionmentioning

confidence: 99%

“…A long‐standing point of debate in cohesive‐particle systems is whether a force‐based or energy‐based description of particle interactions is more appropriate. Estimates of agglomerate size, 19,55–57 constitutive relations for source terms in populations balances, 24,58–63 and regime maps 15,26,62,64–69 are a few prominent examples in which both force‐ and energy‐based descriptions have appeared in the literature, without justification as to why one is more appropriate than the other. Here we aim to decipher the force versus energy conundrum.…”

Section: Discussionmentioning

confidence: 99%

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Toward general regime maps for cohesive‐particle flows: Force versus energy‐based descriptions and relevant dimensionless groups

et al. 2021

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Much confusion exists on whether force‐ or energy‐based descriptions of cohesive‐particle interactions are more appropriate. We hypothesize a force‐based description is appropriate when enduring‐contacts dominate and an energy‐based description when contacts are brief in nature. Specifically, momentum is transferred through force‐chains when enduring‐contacts dominate and particles need to overcome a cohesive force to induce relative motion, whereas particles experiencing brief contacts transfer momentum through collisions and must overcome cohesion‐enhanced energy losses to avoid agglomeration. This hypothesis is tested via an attempt to collapse the dimensionless, dependent variable characterizing a given system against two dimensionless numbers: A generalized bond number, BoG–ratio of maximum cohesive force to the force driving flow, and a new Agglomerate number, Ag–ratio of critical cohesive energy to the granular energy. A gamut of experimental and simulation systems (fluidized bed, hopper, etc.), and cohesion sources (van der Waals, humidity, etc.), are considered. For enduring‐contact systems, collapse occurs with BoG but not Ag, and vice versa for brief‐contact systems, thereby providing support for the hypothesis. An apparent discrepancy with past work is resolved, and new insight into Geldart's classification is gleaned.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Toward general regime maps for cohesive‐particle flows: Force versus energy‐based descriptions and relevant dimensionless groups

et al. 2021

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“…The effect of these contact parameter on the rheological property of granular flow is thoroughly discussed in Refs. [18][19][20][21][22].…”

Section: Methodsmentioning

confidence: 99%

Shear-induced diffusion: the role of granular clusters

Macaulay

Rognon

2021

EPJ Web Conf.

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This paper is concerned with the physical mechanisms controlling shear-induced diffusion in dense granular flows. The starting point is that of the granular random walk occurring in diluted granular flows, which underpins Bagnold’s scaling relating the coefficient of self-diffusion to the grain size and shear rate. By means of DEM simulations of plane shear flows, we measure some deviations from this scaling in dense granular flows with and without contact adhesion. We propose to relate these deviations to the development of correlated motion of grains in these flows, which impacts the magnitude of grain velocity fluctuations and their time persistence.

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“…When sheared granular matter starts to flow and (for large enough strain) reaches a steady state, or critical state [69][70][71], the nowadays widely accepted "classical" (I) -rheology [72] holds. It was recently extended to include friction, softness and cohesion [2,12,13,69,70,[73][74][75], but it does not have a fully tensorial form [76,77], and doubts about its well-posed-ness are still discussed [78][79][80]. Modern experimental techniques [25,71,81,82], also with focus on low confining stress [83], shed new light on classical works on the response to local perturbations [84], jamming and un-jamming [23,[84][85][86][87], in particular by shear [10,49,60,65,[88][89][90], and transient fabric/micro-structure evolution [31,49,55,[91][92][93][94].…”

Section: A Brief History Of Granular Researchmentioning

confidence: 99%

“…7 xy ≈ √ 1∕2 s , but not to strain, , integrated in time over shear rate, ̇= 2̇x y , as discussed in Ref. [75]. 8 Note that (calligraphic) symbols B ≠ B , G ≠ G , and A = A ij , in general, are the (tangent) moduli, representing the second derivatives of the elastic energy density with respect to isotropic and deviatoric elastic strains, or mixed, respectively; symbols B , G are again different and are the secant moduli; for more details see Sects.…”

Section: Overviewmentioning

confidence: 99%

Un-jamming due to energetic instability: statics to dynamics

2021

Self Cite

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Jamming/un-jamming, the transition between solid- and fluid-like behavior in granular matter, is an ubiquitous phenomenon in need of a sound understanding. As argued here, in addition to the usual un-jamming by vanishing pressure due to a decrease of density, there is also yield (plastic rearrangements and un-jamming that occur) if, e.g., for given pressure, the shear stress becomes too large. Similar to the van der Waals transition between vapor and water, or the critical current in superconductors, we believe that one mechanism causing yield is by the loss of the energy’s convexity (causing irreversible re-arrangements of the micro-structure, either locally or globally). We focus on this mechanism in the context of granular solid hydrodynamics (GSH), generalized for very soft materials, i.e., large elastic deformations, employing it in an over-simplified (bottom-up) fashion by setting as many parameters as possible to constant. Also, we complemented/completed GSH by using various insights/observations from particle simulations and calibrating some of the theoretical parameters—both continuum and particle points of view are reviewed in the context of the research developments during the last few years. Any other energy-based elastic-plastic theory that is properly calibrated (top-down), by experimental or numerical data, would describe granular solids. But only if it would cover granular gas, fluid, and solid states simultaneously (as GSH does) could it follow the system transitions and evolution through all states into un-jammed, possibly dynamic/collisional states—and back to elastically stable ones. We show how the un-jamming dynamics starts off, unfolds, develops, and ends. We follow the system through various deformation modes: transitions, yielding, un-jamming and jamming, both analytically and numerically and bring together the material point continuum model with particle simulations, quantitatively. Graphic abstract

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Steady state rheology of homogeneous and inhomogeneous cohesive granular materials

Cited by 27 publications

References 79 publications

Toward general regime maps for cohesive‐particle flows: Force versus energy‐based descriptions and relevant dimensionless groups

Toward general regime maps for cohesive‐particle flows: Force versus energy‐based descriptions and relevant dimensionless groups

Shear-induced diffusion: the role of granular clusters

Un-jamming due to energetic instability: statics to dynamics

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