Pith. sign in

REVIEW 3 major objections 5 minor 46 references

Effects of particle elongation on dense granular flows down a rough inclined plane

T0 review · 3 major / 5 minor · reviewed 2026-08-10 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗ Review JSON

Pith's one-line read This paper shows that the slope of Pouliquen's granular flow rule depends on particle aspect ratio in an S-shaped way, with plateaus for nearly spherical and strongly elongated grains, and packages this dependence into a shape-aware basal…

desk verdict A useful AR-scan of Pouliquen's beta with a real S-curve, but the clumped-sphere corrugation confound in the transition region needs addressing before I'd trust the mechanistic story. read the letter →

arxiv 2501.10626 v1 pith:7TF537I7 submitted 2025-01-18 cond-mat.soft physics.comp-ph

Jixiong Liu , Lu Jing , Thomas Pähtz , Yifei Cui , Gordon G. D. Zhou , Xudong Fu This is my paper · ORCID
classification cond-mat.softphysics.comp-ph PACS 45.70.Mg
keywords granularflowPouliquenruleparticleaspectratioelongationdiscreteelementmethodstoppingthicknessbasalfrictionrheology
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

Granular flows in nature and industry involve non-spherical grains, yet particle-shape effects are usually left out of flow rules. The paper uses discrete-element simulations of clumped-sphere rods sliding down a rough incline, varying the length-to-diameter aspect ratio $\mathrm{AR}$ from 1 to 3. It establishes that Pouliquen's scaling—Froude number proportional to $h/h_{\text{stop}}$—works for every $\mathrm{AR}$ separately, but the proportionality constant $\beta$ is not universal: it stays near 0.22 for $\mathrm{AR}\le 1.3$, rises sharply to about 0.53 between $\mathrm{AR}\approx 1.3$ and 2, then plateaus. The authors capture this with a sigmoidal function of $\mathrm{AR}$ and use it to derive a basal-friction law for shallow avalanche models that depends on flow thickness, Froude number, and aspect ratio. The micromechanical explanation attributes the first plateau to unchanged rotation ability and the second to saturation of orientation, while the paper itself notes that neither microscopic quantity transitions as sharply as $\beta$.

What carries the argument

Pouliquen's flow rule is the skeleton: flows down a rough incline are characterized by the stopping thickness $h_{\text{stop}}(\theta)$ and the collapse of the Froude number $Fr = u/\sqrt{gh}$ against $h/h_{\text{stop}}$ onto a straight line $Fr = \beta\, h/h_{\text{stop}}$. The $h_{\text{stop}}$ curve is fit by $h_{\text{stop}}/d = A(\tan\theta_2 - \tan\theta)/(\tan\theta - \tan\theta_1)$, which yields the dynamic angle of repose $\theta_1$. The shape dependence enters through the fitted slope $\beta$, modelled by the logistic function of Eq. (4). To interpret the S-shape, the paper uses the orientation order parameter $S = (3\langle\cos^2(\alpha_{xz} - \alpha_{xz}^{\text{avg}})\rangle - 1)/2$, the preferred side-view orientation angle $\alpha_{xz}^p$, and the rotation ability $k_\omega$, the slope of layer-averaged angular velocity $\omega$ versus shear rate $\dot{\gamma}$. The argument is that $k_\omega$'s plateau for $\mathrm{AR}\lesssim 1.3$ explains the first plateau in $\beta$, while the saturation of alignment and orientation beyond $\mathrm{AR}\approx 2$ explains the second; Eq. (4) then lifts $\beta$ into a basal friction law for shallow-flow equations.

What would settle it

Perform additional DEM runs at finer $\mathrm{AR}$ increments (about 1.25, 1.35, 1.45) using smoother clumps or true ellipsoids, and compute $k_\omega$ from basal-layer angular velocities rather than layer averages; if $k_\omega$ declines gradually instead of plateauing, or if the S-shape of $\beta(\mathrm{AR})$ shifts or disappears with better-resolved $\mathrm{AR}$ or smoother particles, the proposed explanation and the general sigmoid fail.

Watch

Extended reading notes

Core claim

The central claim is that grain elongation enters Pouliquen's flow rule through a single shape-dependent coefficient. For each aspect ratio tested, all steady flows collapse onto a line $Fr = \beta\, h/h_{\text{stop}}$, but $\beta$ depends on $\mathrm{AR}$ in three regimes: a low plateau ($\beta \approx 0.22$–0.24) for $\mathrm{AR}\lesssim 1.3$, a sharp rise to $\beta\approx 0.53$ for $1.3\lesssim\mathrm{AR}\lesssim 2$, and a high plateau beyond $\mathrm{AR}\approx 2$. Fitting $\beta(\mathrm{AR})$ with the logistic form $\beta_{\mathrm{AR}} = A_2 + (A_1 - A_2)/(1 + (\mathrm{AR}/A_0)^p)$ with $A_0\approx 1.46$, $A_1\approx 0.22$, $A_2\approx 0.53$, $p\approx 17.8$, and combining it with the $h_{\text{stop}}$ fit gives an extended Pouliquen friction law $\mu_b(h, Fr, \mathrm{AR})$. At the particle scale, the paper attributes the low-AR plateau to an essentially unchanged rotation ability $k_\omega$ (the slope of angular velocity versus shear rate) for weakly elongated grains, and the high-AR plateau to saturation of particle alignment and preferred orientation. The authors state that neither $k_\omega$ nor the orientation order parameter $S$ changes as sharply at $\mathrm{AR}\approx 1.3$ as $\beta$ does, so the sharp transition is empirically robust but lacks a single sharp microscopic order parameter.

Load-bearing premise

The load-bearing premise is that the layer-averaged rotation ability $k_\omega$ faithfully measures how particle elongation restricts rotation, and that its flat behavior for $\mathrm{AR}\lesssim 1.3$ is what produces the first plateau in $\beta$; the paper itself concedes that neither $k_\omega$ nor the orientation order parameter transitions as sharply as $\beta$, so if $k_\omega$ is sensitive to layer averaging or to the coarse $\mathrm{AR}$ sampling, the mechanistic explanation would need revision.

Editorial extensions

If this is right

  • For monodisperse elongated grains, Pouliquen's collapse still holds within each aspect ratio, so depth-averaged models can be extended by letting $\beta$ depend on $\mathrm{AR}$.
  • Particle elongation makes flows harder to mobilize—$h_{\text{stop}}$ shifts to larger angles and thicknesses—but this effect saturates around $\mathrm{AR}\approx 2$, after which further elongation changes mobility little.
  • The logistic $\beta(\mathrm{AR})$ relation, combined with the $h_{\text{stop}}$ fit, gives an explicit basal friction law $\mu_b(h, Fr, \mathrm{AR})$ that can be inserted into the mass- and momentum-conservation equations used for shallow granular avalanches.
  • Weakly elongated grains ($\mathrm{AR}\lesssim 1.3$) rotate essentially like spheres, so shape effects in this regime must act through alignment and geometry rather than through rotation.
  • Because neither $k_\omega$ nor $S$ transitions as sharply as $\beta$, a single microscopic order parameter for the sphere-to-rod crossover remains missing; finding it is a concrete next step.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • If the S-shape is generic, natural samples with a broad distribution of grain aspect ratios should smear the transition; an effective $\beta$ for a polydisperse mixture may be a weighted average over $\mathrm{AR}$, which could be tested with binary-AR DEM mixtures.
  • The corrugation sensitivity in the paper's Appendix A suggests that the sharp rise near $\mathrm{AR}\approx 1.4$–1.5 may partly reflect the roughness of clumped-sphere particles, not aspect ratio alone; repeating the sweep with ellipsoids or smoother clumps could shift the transition.
  • The plateau of $k_\omega$ near 0.5, and its possible link to the vorticity-to-shear-rate ratio in fluids, hints that weakly elongated grains might be treated as rotationally spherical in continuum models, with shape entering only through modified contact-level friction—an extension the paper does not make.
  • Because $\beta$ sets depth-averaged speed in avalanche equations, the $\mathrm{AR}$-dependent friction law could be coupled to segregation or erosion models for non-spherical grains, connecting single-flow mobility to deposit patterns.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

3 major / 5 minor

Summary. The paper uses DEM simulations of clumped-sphere particles with aspect ratios AR from 1 to 3 to study dense granular flows down rough inclined planes. For each AR the authors extract h_stop(θ) curves and the Pouliquen scaling Fr versus h/h_stop, showing that the scaling holds individually for each AR but with a slope β that increases with AR in an S-shaped manner: a plateau for AR ≲ 1.3, a sharp rise between 1.3 and 2.0, and a second plateau beyond AR ≈ 2.0. They fit this trend with a four-parameter logistic function (Eq. 4) and combine it with Pouliquen's flow rule to propose a shape-dependent basal friction law (Eq. 7). Microscopic statistics of particle orientation (order parameter S, preferred angle αxz^p) and rotation (kω from the ω–γ̇ relation) are presented to explain the three-regime behavior.

Significance. The systematic sweep over aspect ratio connects the spherical-particle regime with the strongly non-spherical regime, and the suggestion that Pouliquen's scaling survives per AR but not across AR is a useful result for shallow-flow modeling of non-spherical grains. The study is carefully executed: it includes domain-size checks, contact-parameter sensitivity tests, and a comparison with literature data that places the simulation results in context. The machine-generated data are reproducible in principle and the sensitivity checks are a genuine strength. However, the central empirical claim—that β(AR) is S-shaped because of elongation—is undermined by a known confound with clump corrugation, and the microscopic explanation is explicitly acknowledged by the authors themselves to be incomplete. If the confound is resolved, the paper would make a solid contribution to the shape-dependent flow-rule literature.

major comments (3)
  1. [Appendix A, Fig. 8] The central claim that β(AR) is S-shaped due to elongation is confounded with clump corrugation. The convexity C_x (Eq. A1, Fig. 8b) drops from 0.971 at AR=1.3 to 0.917 at AR=1.5 and remains at 0.917 for AR≥1.5, while the sharp rise in β (Fig. 3d, Table II) occurs almost exactly over this same interval and both plateaus coincide with nearly constant C_x. The corrugation sensitivity test in Fig. 8(a) is performed only at AR=3 (C_x=0.917) and shows that increasing P_AR3 changes u/√gd substantially, so a corrugation of the magnitude present in the transition region is dynamically significant. The paper does not test whether the transition region AR=1.3–1.5 is sensitive to the number of spheres in the clump. The authors must either repeat the P_AR3 test at an intermediate AR (e.g., AR=1.4 or 1.5) with sufficient spheres per clump to keep C_x near unity, or use smooth particles (ellipsoids or superquadrics) in the transition region, to isolate elongation from discretization roughness. Without this, the reported S-shape may be an artifact of varying convexity rather than a genuine effect of aspect ratio.
  2. [Section V] The paper overstates its microscopic explanation. The abstract and Section IV claim that the S-shape is understood (e.g., "We understand this S-shaped dependence" and the attribution of the first plateau to unchanged k_ω), but Section V explicitly states that "neither particle alignment (S and αxz^p) nor rotation (k_ω) parameters exhibit a transition at AR ≈ 1.3 that is as sharp as in β." Since the sharp rise between AR=1.3 and 2.0 is the most distinctive feature of the S-shape, the proposed mechanistic account does not explain the phenomenon. The authors should revise the abstract and Section IV to present S, αxz^p, and k_ω as correlated trends that bracket the transition but do not reproduce its sharpness, or provide a new microscopic measure that captures that sharpness.
  3. [Eq. (4), Table II] The logistic fit Eq. (4) has four free parameters (A_0, A_1, A_2, p) for only nine data points, and the transition region is constrained by just three points (AR=1.3, 1.4, 1.5). The sharpness parameter p=17.83 and the asymptotic values A_1 and A_2 are therefore not robust; a small change in one intermediate point would substantially shift the fitted transition. At minimum, the authors should fix A_1 and A_2 to the plateau averages (β≈0.23 and β≈0.53) and fit the remaining two parameters, report confidence intervals, and show sensitivity to excluding each of the three transition points. Alternatively, a piecewise fit with explicit plateau and transition domains would be more transparent than a four-parameter logistic.
minor comments (5)
  1. [Section III.B] In the text, "a sharp transition similar to Fig. 3(c) is not observed" should refer to Fig. 3(d), because Fig. 3(c) shows θ_1(AR) while Fig. 3(d) shows β(AR); as written, the reference is ambiguous.
  2. [Eq. (7)] Equation (7) extends the Pouliquen flow rule by inserting the fitted β_AR from Eq. (4), but the resulting friction law is never validated against an independent simulation (for example, an unsteady or non-uniform flow). A sentence clarifying that Eq. (7) is a proposed closure rather than a tested constitutive law would be appropriate.
  3. [Appendix A] The text says C_x "remains unaltered for AR ≥ 1.5," but the reader must infer from the Fig. 8(b) caption that C_x is identical for AR=1.5, 2.0, 2.5, and 3.0 (all equal to 0.917). Stating this explicitly in the text would be clearer.
  4. [Eq. (3)] The order parameter S in Eq. (3) uses αxz^avg, the average orientation angle, which is not necessarily the nematic director for the skewed and broad distributions shown in Fig. 4(b). The definition should be clarified, or the standard nematic director (the eigenvector of the second-moment tensor) should be used to avoid ambiguity.
  5. [Table II] Table II reports large fitting errors for θ_2 (e.g., 60.99° ± 8.16° for AR=2.5), and the authors state that these errors do not affect their analysis. This should be justified explicitly, for example by showing that β is insensitive to plausible variations of θ_2 within its fitting uncertainty.

Circularity Check

0 steps flagged · score 0.0 of 10

No circularity: the beta-AR curve is measured, and Eqs. (4) and (7) are explicitly empirical fits, not disguised predictions.

full rationale

The central result of the paper is empirical: beta is obtained by fitting each AR dataset to Eq. (2) after independently extracting hstop and Fr-h/hstop relations from DEM simulations. No equation defines beta in terms of the microscopic statistics or vice versa, so the claimed S-shaped dependence is not self-definitional. Eq. (4) is an explicit logistic function fit to the measured beta-AR data, and the paper labels it an empirical sigmoidal function; it is not presented as a first-principles prediction. Eq. (7) is derived by algebraically combining Eqs. (1) and (2) with beta replaced by beta_AR, which is a parameterization for shallow-flow modeling, not an independent validation of Eq. (4). The microscopic explanation uses separately measured quantities (k_omega, S, alpha_pxz) that are not used to construct beta, and the paper openly concedes in Sec. V that neither S nor k_omega exhibits a transition as sharp as beta, so there is no hidden circular reliance on the microscopic statistics. Self-citations, such as ref. [23] for base roughness and ref. [21] for domain size, are used only to justify standard simulation choices and do not carry the main argument. The possible confounding of the beta-AR trend with clump convexity variation (Appendix A, Fig. 8) is a correctness/validity concern, not a circularity, because it does not reduce any claimed result to its own inputs by construction.

Assumptions & free parameters 6 free parameters · 5 assumptions · 0 invented entities

The central claim is an empirical scaling relation extracted from DEM data. It rests on the usual Pouliquen framework, the clump-sphere representation of elongation, and contact parameters chosen from the literature. The main fitted inputs are the h_stop parameters, beta, k_omega, and the four constants of the logistic curve. No new physical entities are introduced.

free parameters (6)
  • h_stop fitting parameters theta1, theta2, A = theta1 19.40 to 28.86 deg; theta2 37.68 to 60.99 deg; A 0.44 to 2.71
    Fitted per AR to the h_stop(theta) curve using Eq. (1); listed in Table II. These parameters are inputs to the extended flow rule Eq. (7).
  • Pouliquen slope beta = 0.219 to 0.541 across AR
    Fitted slope of Fr versus h/h_stop per AR using Eq. (2); listed in Table II. This is the central dependent variable of the paper.
  • Logistic parameters A0, A1, A2, p = A0=1.46, A1=0.22, A2=0.53, p=17.83
    Fit of Eq. (4) to the beta-AR data. The model is empirical and is not validated on independent data.
  • Rotation ability k_omega = approx. 0.5 for AR<=1.3, decreasing to approx. 0.35 at AR=3
    Slope of the angular velocity versus shear rate relation in Fig. 6. Used as the microscopic rotation-ability proxy that is claimed to explain the first plateau.
  • Contact model parameters (k_n, k_t/k_n, e, mu) = k_n=7.5e5 mg/d, k_t/k_n=1, e=0.56, mu=0.5
    Chosen from literature and sensitivity tested in Appendix C. These are input choices, not fitted to the target beta-AR curve, but they affect all measured velocities.
  • Clump sphere count PAR3 = 5
    Number of overlapping spheres used to represent AR=3 particles. Chosen because corrugation effects saturate beyond PAR3=5 in Appendix A.
assumptions (5)
  • domain assumption Pouliquen scaling Fr = beta h/h_stop holds for each AR
    The paper uses Eq. (2) as the analysis framework and checks collapse visually for each AR. The scaling law itself is taken from prior literature, not derived here.
  • domain assumption h_stop is a single-valued function of theta obtained by a bracketing protocol
    Section II B defines the stopping angle as the mean between the smallest sustaining and largest non-sustaining angles after initializing at 60 degrees. This assumes the stopping transition is not strongly history dependent.
  • domain assumption Clumps of overlapping spheres with PAR3=5 faithfully represent smooth elongated particles
    Appendix A shows corrugation effects decrease mobility and that convexity remains above 0.9 for all AR, but the representation is still an approximation that could affect quantitative beta values.
  • domain assumption Bulk-averaged orientation and rotation statistics capture the microscopic mechanisms controlling the depth-averaged flow rule
    Used in Section III C. Flow-depth insensitivity is shown for selected cases, but no causal closure connects these statistics to beta, and the authors admit the transition in beta is sharper than in any measured microscopic quantity.
  • domain assumption Linear spring-dashpot contact with the chosen parameters reproduces dense granular rheology
    Section II A and Appendix C. This is a standard modeling assumption in the DEM community, with sensitivity tests that do not fully remove the approximation.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Effects of particle elongation on dense granular flows down a rough inclined plane." pith.science (2026). https://pith.science/paper/7TF537I7

@misc{pith2026250110626,
  author       = {Pith},
  title        = {Pith review of: Effects of particle elongation on dense granular flows down a rough inclined plane},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/7TF537I7}},
  note         = {Machine review of arXiv:2501.10626}
}
abstract

Granular materials in nature are nearly always non-spherical, but particle shape effects in granular flow remain largely elusive. This study uses discrete element method simulations to investigate how elongated particle shapes affect the mobility of dense granular flows down a rough incline. For a range of systematically varied particle length-to-diameter aspect ratios (AR), we run simulations with various flow thicknesses $h$ and slope angles $\theta$ to extract the well-known $h_\textrm{stop}(\theta)$ curves (below which the flow ceases) and the $Fr$-$h/h_\textrm{stop}$ relations following Pouliquen's approach, where $Fr=u/\sqrt{gh}$ is the Froude number, $u$ is the mean flow velocity, and $g$ is the gravitational acceleration. The slope $\beta$ of the $Fr$-$h/h_\textrm{stop}$ relations shows an intriguing S-shaped dependence on AR, with two plateaus at small and large AR, respectively, transitioning with a sharp increase. We understand this S-shaped dependence by examining statistics of particle orientation, alignment, and hindered rotation. We find that the rotation ability of weakly elongated particles ($\textrm{AR}\lesssim1.3$) remains similar to spheres, leading to the first plateau in the $\beta$-AR relation, whereas the effects of particle orientation saturates beyond $\textrm{AR}\approx2.0$, explaining the second plateau. An empirical sigmoidal function is proposed to capture this non-linear dependence. The findings are expected to enhance our understanding of how particle shape affects the flow of granular materials from both the flow- and particle-scale perspectives.

Figures

Figures reproduced from arXiv: 2501.10626 by the authors.

Figure 1
Figure 1. FIG. 1. Setup and primary notation. (a) Geometry of a typical elongated particle. (b) A snapshot of the DEM simulation. [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. FIG. 2. Typical flow behaviors of spherical (AR = 1) and elongated (AR = 1 [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. FIG. 3. Flow behavior with varying particle aspect ratio (AR). (a) [PITH_FULL_IMAGE:figures/full_fig_p006_3.png] view at source ↗
Figures from the paper (8 more)
Figure 4
Figure 4. Figure 4: FIG. 4. Particle alignment and orientation for AR ranging from 1.1 to 3 (with [PITH_FULL_IMAGE:figures/full_fig_p007_4.png]
Figure 5
Figure 5. Figure 5: FIG. 5. Layerwise measurements of flow kinematics for AR = 1 [PITH_FULL_IMAGE:figures/full_fig_p009_5.png]
Figure 6
Figure 6. Figure 6: FIG. 6. Rotational statistics for varying AR. (a) Non-dimensional angular velocity [PITH_FULL_IMAGE:figures/full_fig_p009_6.png]
Figure 7
Figure 7. Figure 7: FIG. 7. Comparison of our key results with data from the literature [1, 18, 25, 26, 38, 39]. (a) Fitted parameter [PITH_FULL_IMAGE:figures/full_fig_p010_7.png]
Figure 8
Figure 8. Figure 8: FIG. 8. Effects of particle corrugation. (a) Dimensionless velocity [PITH_FULL_IMAGE:figures/full_fig_p013_8.png]
Figure 9
Figure 9. Figure 9: FIG. 9. Effects of computational domain size. (a) Dimensionless velocity [PITH_FULL_IMAGE:figures/full_fig_p013_9.png]
Figure 10
Figure 10. Figure 10: FIG. 10. Sensitivity tests for key model parameters. Dimensionless velocity [PITH_FULL_IMAGE:figures/full_fig_p014_10.png]
Figure 11
Figure 11. Figure 11: FIG. 11. Improved Pouliquen-Jenkins flow rule. (a) Froude number [PITH_FULL_IMAGE:figures/full_fig_p015_11.png]

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

46 extracted references · 45 canonical work pages

  1. [1]

    Particle alignment and orientation Particle alignment along a preferential orientation is perhaps the most straightforward effect of elongated particle shapes in granular flows [27–29]. To characterize the statistics of the particle orientation, particles are projected onto the xy (top view) and xz (side view) planes to define angles αxy and αxz, respecti...

    work page

  2. [2]

    Particle angular velocity Particle angular velocity is a crucial parameter that reflects the ability of particles to rotate during the flow. To understand how AR affects the rotation dynamics of elongated particles (hence the flow mobility), we measure the mean rotational velocity of particles around the y-axis [see inset of Fig. 4(b)], denoted by ω, at a...

    work page

  3. [3]

    (0.5 mm glass beads) and B¨ orzs¨ onyi and Ecke [18] (0.51 mm glass beads) for experiments, and Silbert et al

    work page

  4. [4]

    Pouliquen and Y

    O. Pouliquen and Y. Forterre, Friction law for dense granular flows: application to the motion of a mass down a rough inclined plane, Journal of Fluid Mechanics 453, 133 (2002)

    work page 2002

  5. [5]

    Forterre and O

    Y. Forterre and O. Pouliquen, Long-surface-wave instability in dense granular flows, Journal of Fluid Mechanics 486, 21 (2003). 15 0.3 0.4 0.5 0.6 0.7 0.0 0.1 0.2 0.3 0.4 0.5 0.6 This work Bö rzsö nyi2007 (Sand and glass beads) Börzsönyi2007 (Copper, η=0.33) Börzsönyi2007 (Copper, η=0.50) tanq1 bPJFR 0 10 20 30 40 50 600 2 4 6 8 AR=1.0 AR=1.1 AR=1.2 AR=1....

    work page 2003

  6. [6]

    P. Tahmasebi, A state-of-the-art review of experimental and computational studies of granular materials: properties, advances, challenges, and future directions, Progress in Materials Science , 101157 (2023)

    work page 2023

  7. [7]

    Weinhart, A

    T. Weinhart, A. R. Thornton, S. Luding, and O. Bokhove, Closure relations for shallow granular flows from particle simulations, Granular Matter 14, 531 (2012)

    work page 2012

  8. [8]

    Qian, R.-R

    Y.-C. Qian, R.-R. Cai, and L.-Z. Zhang, Numerical simulation of non-spherical microparticles’ deposition on single fiber, Physics of Fluids 36 (2024)

    work page 2024

Show all 46 references
  1. [9]

    F. D. C´ u˜ nez, D. Patel, and R. C. Glade, How particle shape affects granular segregation in industrial and geophysical flows, Proceedings of the National Academy of Sciences 121, e2307061121 (2024)

    2024

  2. [10]

    R. P. Jones, J. M. Ottino, P. B. Umbanhowar, and R. M. Lueptow, Predicting segregation of nonspherical particles, Physical Review Fluids 6, 054301 (2021)

    2021

  3. [11]

    E. Deal, J. G. Venditti, S. J. Benavides, R. Bradley, Q. Zhang, K. Kamrin, and J. T. Perron, Grain shape effects in bed load sediment transport, Nature 613, 298 (2023)

    2023

  4. [12]

    Mandal and D

    S. Mandal and D. Khakhar, A study of the rheology and micro-structure of dumbbells in shear geometries, Physics of Fluids 30 (2018)

    2018

  5. [13]

    Cassel, J

    M. Cassel, J. Lav´ e, A. Recking, J.-R. Malavoi, and H. Pi´ egay, Bedload transport in rivers, size matters but so does shape, Scientific Reports 11, 508 (2021)

    2021

  6. [14]

    B¨ orzs¨ onyi, B

    T. B¨ orzs¨ onyi, B. Szab´ o, G. T¨ or¨ os, S. Wegner, J. T¨ or¨ ok, E. Somfai, T. Bien, and R. Stannarius, Orientational order and alignment of elongated particles induced by shear, Physical Review Letters 108, 228302 (2012)

    2012

  7. [15]

    Hao and Y

    J. Hao and Y. Guo, Rheology of sheared polyhedral granular materials in inclined flows, Physics of Fluids 35 (2023)

    2023

  8. [16]

    Forterre and O

    Y. Forterre and O. Pouliquen, Flows of dense granular media, Annual Review of Fluid Mechanics 40, 1 (2008)

    2008

  9. [17]

    J.-Y. Nie, Y. Cui, G. Wang, R. Wang, N. Zhang, L. Zhang, and Z. Wu, A comprehensive numerical investigation of multi-scale particle shape effects on small strain stiffness of sands, G´ eotechnique, (2024)

    2024

  10. [18]

    Y. Qian, S. J. Lee, E. Tutumluer, Y. M. Hashash, and J. Ghaboussi, Role of initial particle arrangement in ballast mechanical behavior, International Journal of Geomechanics 18, 04017158 (2018)

    2018

  11. [19]

    MiDi, On dense granular flows, The European Physical Journal E 14, 341 (2004)

    G. MiDi, On dense granular flows, The European Physical Journal E 14, 341 (2004)

    2004

  12. [20]

    Y. Guo, C. Wassgren, W. Ketterhagen, B. Hancock, B. James, and J. Curtis, A numerical study of granular shear flows of rod-like particles using the discrete element method, Journal of Fluid Mechanics 713, 1 (2012)

    2012

  13. [21]

    Pouliquen, Scaling laws in granular flows down rough inclined planes, Physics of Fluids 11, 542 (1999)

    O. Pouliquen, Scaling laws in granular flows down rough inclined planes, Physics of Fluids 11, 542 (1999)

    1999

  14. [22]

    B¨ orzs¨ onyi and R

    T. B¨ orzs¨ onyi and R. E. Ecke, Flow rule of dense granular flows down a rough incline, Physical Review E76, 031301 (2007)

    2007

  15. [23]

    J. Zhao, S. Zhao, and S. Luding, The role of particle shape in computational modelling of granular matter, Nature Reviews Physics 5, 505 (2023)

    2023

  16. [24]

    R. C. Hidalgo, B. Szab´ o, K. Gillemot, T. B¨ orzs¨ onyi, and T. Weinhart, Rheological response of nonspherical granular flows down an incline, Physical Review Fluids 3, 074301 (2018). 16

    2018

  17. [25]

    A. Pol, R. Artoni, and P. Richard, Unified scaling law for wall friction in laterally confined flows of shape anisotropic particles, Physical Review Fluids 8, 084302 (2023)

    2023

  18. [26]

    [25] for simulations

    and Thornton et al. [25] for simulations. Silbert et al. [26] used the Hertzian contact model with µ = 0 .5, kn = 2 × 105mg/d, kt = 2 /7kn, normal viscoelastic constants γn = 50 p g/d, and tangential viscoelastic constants γt = γn/2. Thornton et al. [25] used the same paramete...

    2023

  19. [27]

    L. E. Silbert, D. Erta¸ s, G. S. Grest, T. C. Halsey, D. Levine, and S. J. Plimpton, Granular flow down an inclined plane: Bagnold scaling and rheology, Physical Review E 64, 051302 (2001)

    2001

  20. [28]

    L. Jing, C. Y. Kwok, Y. F. Leung, and Y. D. Sobral, Characterization of base roughness for granular chute flows, Physical Review E 94, 052901 (2016)

    2016

  21. [29]

    A. R. Thornton, T. Weinhart, S. Luding, and O. Bokhove, Frictional dependence of shallow-granular flows from discrete particle simulations, The European Physical Journal E 35, 1 (2012)

    2012

  22. [30]

    L. E. Silbert, J. W. Landry, and G. S. Grest, Granular flow down a rough inclined plane: transition between thin and thick piles, Physics of Fluids 15, 1 (2003)

    2003

  23. [31]

    Guo and J

    Y. Guo and J. S. Curtis, Discrete element method simulations for complex granular flows, Annual Review of Fluid Mechanics 47, 21 (2015)

    2015

  24. [32]

    Y. Guo, C. Wassgren, B. Hancock, W. Ketterhagen, and J. Curtis, Granular shear flows of flat disks and elongated rods without and with friction, Physics of Fluids 25 (2013)

    2013

  25. [33]

    Nadler, F

    B. Nadler, F. Guillard, and I. Einav, Kinematic model of transient shape-induced anisotropy in dense granular flow, Physical Review Letters 120, 198003 (2018)

    2018

  26. [34]

    A. Pol, R. Artoni, P. Richard, P. R. N. da Concei¸ c˜ ao, and F. Gabrieli, Kinematics and shear-induced alignment in confined granular flows of elongated particles, New Journal of Physics 24, 073018 (2022)

    2022

  27. [35]

    R. Cai, H. Xiao, I. C. Christov, and Y. Zhao, Diffusion of ellipsoidal granular particles in shear flow, AIChE Journal 67, e17109 (2021)

    2021

  28. [36]

    D. B. Nagy, P. Claudin, T. B¨ orzs¨ onyi, and E. Somfai, Flow and rheology of frictional elongated grains, New Journal of Physics 22, 073008 (2020)

    2020

  29. [37]

    G. K. Batchelor, An Introduction to Fluid Dynamics (Cambridge University Press, Cambridge, UK, 1967)

    1967

  30. [38]

    Barrett, The shape of rock particles, a critical review, Sedimentology 27, 291 (1980)

    P. Barrett, The shape of rock particles, a critical review, Sedimentology 27, 291 (1980)

    1980

  31. [39]

    L. Zhao, S. Zhang, D. Huang, X. Wang, and Y. Zhang, 3d shape quantification and random packing simulation of rock aggregates using photogrammetry-based reconstruction and discrete element method, Construction and Building Materials 262, 119986 (2020)

    2020

  32. [40]

    M. Fan, D. Su, and X. Chen, Improved method for generating sand assembly with wide range of aspect ratios and angularities based on insights gained from comparative study of existing techniques, Computers and Geotechnics 155, 105231 (2023)

    2023

  33. [41]

    S. J. Blott and K. Pye, Particle shape: a review and new methods of characterization and classification, Sedimentology 55, 31 (2008)

    2008

  34. [42]

    Edwards, S

    A. Edwards, S. Viroulet, B. Kokelaar, and J. Gray, Formation of levees, troughs and elevated channels by avalanches on erodible slopes, Journal of Fluid Mechanics 823, 278 (2017)

    2017

  35. [43]

    B. Fan, T. Pong´ o, R. Cruz Hidalgo, and T. B¨ orzs¨ onyi, Effect of particle shape on the flow of an hourglass, Physical Review Letters 133, 058201 (2024)

    2024

  36. [44]

    S. B. Savage and K. Hutter, The motion of a finite mass of granular material down a rough incline, Journal of Fluid Mechanics 199, 177 (1989)

    1989

  37. [45]

    Su and W

    D. Su and W. Yan, Prediction of 3d size and shape descriptors of irregular granular particles from projected 2d images, Acta Geotechnica 15, 1533 (2020)

    2020

  38. [46]

    R. D. Mindlin, Compliance of elastic bodies in contact, Journal of Applied Mechanics 16, 259 (1949)

    1949

Pith tools

Reviewed August 10, 2026 · model on record in the stance chip above.