Next Article in Journal
2D Runout Modelling of Hillslope Debris Flows, Based on Well-Documented Events in Switzerland
Next Article in Special Issue
A Review of Russian Snow Avalanche Models—From Analytical Solutions to Novel 3D Models
Previous Article in Journal
Distinguishing between Deep-Water Sediment Facies: Turbidites, Contourites and Hemipelagites
Previous Article in Special Issue
Numerical Simulation of a Debris Flow on the Basis of a Two-Dimensional Continuum Body Model
Open AccessArticle

Simple Particle Model for Low-Density Granular Flow Interacting with Ambient Fluid

1
Center for Transdisciplinary Research, Niigata University, 8050 Ikarashi-nino-cho, Nishi-ku, Niigata 950-2181, Japan
2
Department of Mathematical and Life Sciences, Hiroshima University, 1-3-1, Kagamiyama, Higashi-Hiroshima 739-8526, Japan
*
Author to whom correspondence should be addressed.
Geosciences 2020, 10(2), 69; https://doi.org/10.3390/geosciences10020069
Received: 13 January 2020 / Revised: 4 February 2020 / Accepted: 8 February 2020 / Published: 13 February 2020
(This article belongs to the Special Issue Snow Avalanche Dynamics)
To understand the time evolutions of frontal speed and shape in a low-density granular flow, we propose a simple particle model. This model solves the equation of motion for each particle and simulates the time evolution of low-density granular flow. Spherical particles constituting a low-density granular flow slide on a slope at a steeper angle than the angle of repose. The particle motion is determined based on three forces: gravity as the driving force, repulsive force due to particle collision, and drag force due to the particle interaction through the ambient fluid. Two-dimensional numerical simulations of this model are conducted on the slope: the xy plane parallel to the slope and the xz plane perpendicular to the slope. In the xy plane, particles aggregate at the moving front of the granular flow, and subsequently, flow instability occurs as a wavy pattern. This flow pattern is caused by the interparticle interaction arising from the drag force. Additionally, a vortex convection of particles is formed inside the aggregations. Simultaneously, particle aggregation is also found at the moving front of the granular flow in the xz plane. The aggregation resembles a head–tail structure, where the frontal angle against the slope approaches 60 from a larger angle as time progresses. Comparing the numerical result by varying the particle size reveals that the qualitative dynamics of the granular flow are independent of particle size. Although the model is not realistic, our study presents a new particle-based approach that elucidates the dynamics of low-density granular flow.
Keywords: granular avalanches; mathematical modeling; particle model; numerical simulation; pattern formation granular avalanches; mathematical modeling; particle model; numerical simulation; pattern formation
MDPI and ACS Style

Niiya, H.; Awazu, A.; Nishimori, H. Simple Particle Model for Low-Density Granular Flow Interacting with Ambient Fluid. Geosciences 2020, 10, 69.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop