Observations of grain-scale interactions and simulation of dry granular flows in a large-scale flume

Bryant, Sarah; Take, W. Andy; Bowman, Elisabeth T.

doi:10.1139/cgj-2013-0425

Cited by 38 publications

(28 citation statements)

References 43 publications

(42 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The granular landslide material is made of ceramic beads that are 3 mm in diameter (average diameter of 3.02 mm with a standard deviation of 0.66 mm) and are nominally spherical in shape (average sphericity 0.945 with a standard deviation of 0.026, where a sphericity score of unity represents a perfect sphere). This material has a dry unit weight of 14.8 kN·m −3 , specific gravity of 2.4, and a static critical state friction angle of 33.7° [ Bryant et al ., ; Raymond , ]. An experimental study on dry granular flows by Bryant et al .…”

Section: Physical Modelmentioning

confidence: 99%

Tsunamis generated by long and thin granular landslides in a large flume

et al. 2017

View full text Add to dashboard Cite

In this experimental study, granular material is released down slope to investigate landslide‐generated waves. Starting with a known volume and initial position of the landslide source, detailed data are obtained on the velocity and thickness of the granular flow, the shape and location of the submarine landslide deposit, the amplitude and shape of the near‐field wave, the far‐field wave evolution, and the wave runup elevation on a smooth impermeable slope. The experiments are performed on a 6.7 m long 30° slope on which gravity accelerates the landslides into a 2.1 m wide and 33.0 m long wave flume that terminates with a 27° runup ramp. For a fixed landslide volume of 0.34 m3, tests are conducted in a range of still water depths from 0.05 to 0.50 m. Observations from high‐speed cameras and measurements from wave probes indicate that the granular landslide moves as a long and thin train of material, and that only a portion of the landslide (termed the “effective mass”) is engaged in activating the leading wave. The wave behavior is highly dependent on the water depth relative to the size of the landslide. In deeper water, the near‐field wave behaves as a stable solitary‐like wave, while in shallower water, the wave behaves as a breaking dissipative bore. Overall, the physical model observations are in good agreement with the results of existing empirical equations when the effective mass is used to predict the maximum near‐field wave amplitude, the far‐field amplitude, and the runup of tsunamis generated by granular landslides.

show abstract

Section: Physical Modelmentioning

confidence: 99%

Tsunamis generated by long and thin granular landslides in a large flume

et al. 2017

View full text Add to dashboard Cite

show abstract

“…It does this by tracking the image texture (i.e., the spatial variation of brightness) of subregions or "patches" of the original image in subsequent frames. The original version of GeoPIV was modified to the needs of the present work by supporting a static mesh of interrogation patches with position and geometry fixed in all images, rather than tracking one patch over the course of several images (Bryant et al 2015). In the analysis, the granular flow moves through the patches.…”

Section: Velocity Measurementsmentioning

confidence: 99%

Visualization of dominant stress-transfer mechanisms in experimental debris flows of different particle-size distribution

Sanvitale

Bowman

2017

Can. Geotech. J.

Self Cite

View full text Add to dashboard Cite

Physical modelling of debris flow in a small-scale flume has been carried out to investigate the internal stress-transfer mechanisms within unsteady, saturated, and segregating granular free-surface flows. Measurements of the internal velocity fields within model flows were obtained via planar laser-induced fluorescence and particle image velocimetry. Normalized velocity profiles taken at a section over the flow duration were found to essentially collapse onto a single curve, the shape of which was dependent on the particle-size distribution. While all flows exhibited internal basal slip and shear, for tests on well-graded materials that are most representative of debris flows, the shear rate was found to reduce towards the surface to near-zero, exhibiting near plug-flow. Dimensional analysis shows that particles of different size within these flows experienced different dominant stress-transfer mechanisms -frictional, collisional or viscous. Rapid grain-size segregation therefore is both due to and results in different modes of stress transfer within a single flow. This means that in a segregating and hence, stratified system, different flow regimes will act concurrently at microscale and mesoscale. Results highlight the complexity of debris flows, so that it may be undesirable to ascribe a single microscale constitutive behaviour throughout, and further calls into question the concept of flow regimes for debris flows based on bulk measurements.Key words: debris flow, dimensionless number, flow regime, plane laser-induced fluorescence, flume model tests.Résumé : La modélisation physique de l'écoulement des débris dans un canal à petite échelle a été réalisée pour étudier les mécanismes de transfert de contraintes internes au sein des flux à surface libre granulaires instables, saturés et séparés. Les mesures des champs de vitesse internes au sein des flux modèles ont été obtenues par vélocimétrie à fluorescence induite laser plane a par Image de particule. Les profils de vitesse normalisés pris à une section sur la durée d'écoulement ont été trouvés à se replier essentiellement sur une seule courbe, dont la forme était dépendante à la distribution de la taille des particules. Alors que tous les flux ont exposé un glissement basal interne et de cisaillement, pour les essais sur des matériaux bien classés qui sont les plus représentatifs des flux de débris, le taux de cisaillement a été trouvé à se réduire vers la surface près de zéro, présentant presque un écoulement piston. L'analyse dimensionnelle montre que des particules de taille différente au sein de ces flux ont connu différents mécanismes de transfert de contrainte dominante -de frottement, collisionnel, ou visqueux. La ségrégation rapide à taille de grain est donc à la fois en raison de résultats et dans différents modes de transfert de contrainte dans un seul flux. Cela signifie que dans un système de ségrégation et donc, stratifié, les différents régimes d'écoulement agissent simultané-ment à l'échelle micro et méso. Les résultats mettent en...

show abstract

“…the spatial variation of brightness) of sub-regions or "patches" of the original image in subsequent frames. The original version of GeoPIV was modified to examine granular flow behaviour by supporting a static mesh of interrogation patches with position and geometry fixed in all images [32]. The meshes were composed of a single column of square (Fig.…”

Section: Image Processingmentioning

confidence: 99%

Using PIV to measure granular temperature in saturated unsteady polydisperse granular flows

Sanvitale

Bowman

2016

Granular Matter

Self Cite

View full text Add to dashboard Cite

The motion of debris flows, gravity-driven fast moving mixtures of rock, soil and water can be interpreted using the theories developed to describe the shearing motion of highly concentrated granular fluid flows. Frictional, collisional and viscous stress transfer between particles and fluid characterizes the mechanics of debris flows. To quantify the influence of collisional stress transfer, kinetic models have been proposed. Collisions among particles result in random fluctuations in their velocity that can be represented by their granular temperature, T.

show abstract

Observations of grain-scale interactions and simulation of dry granular flows in a large-scale flume

Cited by 38 publications

References 43 publications

Tsunamis generated by long and thin granular landslides in a large flume

Tsunamis generated by long and thin granular landslides in a large flume

Visualization of dominant stress-transfer mechanisms in experimental debris flows of different particle-size distribution

Using PIV to measure granular temperature in saturated unsteady polydisperse granular flows

Contact Info

Product

Resources

About