scholarly journals Experiments on deaerating granular flows and implications for pyroclastic flow mobility

2002 ◽  
Vol 29 (16) ◽  
pp. 40-1-40-4 ◽  
Author(s):  
O. Roche ◽  
M. Gilbertson ◽  
J. C. Phillips ◽  
R. S. J. Sparks
Keyword(s):  
Pyroclastic Flow ◽  
Granular Flows ◽  
Flow Mobility

scholarly journals Stress level effect on mobility of dry granular flows of angular rock fragments

Landslides ◽  
2021 ◽  
Author(s):  
B. Cagnoli
Keyword(s):  
Stress Level ◽  
Granular Flow ◽  
High Stress ◽  
Granular Flows ◽  
Flow Dynamics ◽  
Small Scale ◽  
Flow Volume ◽  
Rock Fragments ◽  
Rock Avalanches ◽  
Flow Mobility

AbstractGranular flows of angular rock fragments such as rock avalanches and dense pyroclastic flows are simulated numerically by means of the discrete element method. Since large-scale flows generate stresses that are larger than those generated by small-scale flows, the purpose of these simulations is to understand the effect that the stress level has on flow mobility. The results show that granular flows that slide en mass have a flow mobility that is not influenced by the stress level. On the contrary, the stress level governs flow mobility when granular flow dynamics is affected by clast agitation and collisions. This second case occurs on a relatively rougher subsurface where an increase of the stress level causes an increase of flow mobility. The results show also that as the stress level increases, the effect that an increase of flow volume has on flow mobility switches sign from causing a decrease of mobility at low stress level to causing an increase of mobility at high stress level. This latter volume effect corresponds to the famous Heim’s mobility increase with the increase of the volume of large rock avalanches detected so far only in the field and for this reason considered inexplicable without resorting to extraordinary mechanisms. Granular flow dynamics is described in terms of dimensionless scaling parameters in three different granular flow regimes. This paper illustrates for each regime the functional relationship of flow mobility with stress level, flow volume, grain size, channel width, and basal friction.

Database for geologic maps of pyroclastic-flow and related deposits of the 1980 eruptions of Mount St. Helens, Washington

Data Series ◽  
2017 ◽  
Author(s):  
Andrew J. Furze ◽  
Joseph A. Bard ◽  
Joel Robinson ◽  
David W. Ramsey ◽  
Mel A. Kuntz ◽  
...  
Keyword(s):  
Pyroclastic Flow ◽  
Geologic Maps ◽  
Mount St Helens

Discrete Boltzmann Equation model of polydisperse shallow granular flows

2019 ◽  
Vol 113 ◽  
pp. 107-116 ◽  
Author(s):  
Michele La Rocca ◽  
Andrea Montessori ◽  
Pietro Prestininzi ◽  
Lakshmanan Elango
Keyword(s):  
Boltzmann Equation ◽  
Granular Flows ◽  
Equation Model ◽  
Discrete Boltzmann Equation

scholarly journals Nonlocal Effects Reflect the Jamming Criticality in Frictionless Granular Flows Down Inclines

2021 ◽  
Vol 126 (22) ◽  
Author(s):  
Hugo Perrin ◽  
Matthieu Wyart ◽  
Bloen Metzger ◽  
Yoël Forterre
Keyword(s):  
Granular Flows ◽  
Nonlocal Effects

scholarly journals Self-diffusion scalings in dense granular flows

Soft Matter ◽  
2021 ◽  
Author(s):  
Riccardo Artoni ◽  
Michele Larcher ◽  
James T. Jenkins ◽  
Patrick Richard
Keyword(s):  
Shear Rate ◽  
Solid Fraction ◽  
Granular Flows ◽  
The Self ◽  
Granular Temperature ◽  
Restitution Coefficient ◽  
Self Diffusion ◽  
Diffusivity Tensor ◽  
Dense Granular Flows

The self-diffusivity tensor in homogeneously sheared dense granular flows is anisotropic. We show how its components depend on solid fraction, restitution coefficient, shear rate, and granular temperature.

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