scholarly journals Research on the Obstruction Process of Rigid Netting Barriers toward Granular Flow

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Yunyun Fan ◽  
Fengyuan Wu
Keyword(s):  
Discrete Element Method ◽  
Granular Flow ◽  
Engineering Application ◽  
Time History ◽  
Discrete Element ◽  
Primary Concern ◽  
Size Segregation ◽  
Protective Structures ◽  
The Impact ◽  
Element Method

With the advantages of a simple structure and rapid construction, the rigid netting barrier (RNB) exerts a good obstruction effect on granular flow and is a common engineering measure used to prevent geological disasters in the form of granular flows. However, due to the limitations of current measuring and testing techniques, it is difficult to obtain an accurate measurement of the granular flow velocity and the impact force of granular flow on the mesh structures that are of primary concern in the design of protective structures. To study the characteristics of the obstruction process of RNBs toward granular flow, a typical impact experiment involving granular flow was numerically simulated by the discrete element method, and the correctness and effectiveness of the calculation method were also verified. On this basis, the discrete element method was applied to simulate the obstruction process affecting granular flow under different RNB setting conditions, and the calculation results clearly present the phenomena that occur during the obstruction process of RNBs toward granular flow, such as “run-up,” “overflow,” “passing-through,” and “grain-size segregation.” By analyzing the effects of these phenomena on the obstruction efficiency and the time history of the forces acting on the RNB, the rational setting of an RNB was further discussed. This study can provide a reference for the engineering application of RNB.

scholarly journals Analysis of Wet Soil Granular Flow down Inclined Chutes Using Discrete Element Method

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2399
Author(s):  
Chuan Zhao ◽  
Linlin Jiang ◽  
Xin Lu ◽  
Xiang Xiao
Keyword(s):  
Surface Energy ◽  
Discrete Element Method ◽  
Granular Flow ◽  
Soil Structure ◽  
Geometric Model ◽  
Granular Matter ◽  
Discrete Element ◽  
Runout Distance ◽  
The Impact ◽  
Element Method

This paper presents numerical simulation and analysis of two numerical experiments of wet soil granular flow down inclined chutes based on the JKR(Johnson-Kendall-Roberts)-cohesion model of the discrete element method. JKR is a cohesive contact model, which can reflect the influence of van der Waals forces in the contact range to simulate cohesive granular matter. A surface energy coefficient kw was proposed to reflect the liquid surface tension between particles, and maximum surface energy (γmax) of wet soil composed of uniform particles was obtained at 0.2 J/m2. Computational results show that surface energy (γ) and granular size play significant roles in the simulation of wet soil granular flow. The larger surface energy is, and the stronger of adhesion between soil grains. Besides, surface energy also has a great effect on the average velocity and kinetic energy of the moist soil avalanches. With baffles on both sides of the inclined chute, the dry soil granular flow has the longest runout distance on the horizontal plane; with the increase of surface energy, the runout distance decreased gradually. However, without baffles on both sides of the geometric model, the runout distance of wet soil granular flow is farther, though expansion to the sides is more obvious. Wet soil with larger grains requires larger surface energy to maintain the soil structure intact during the sliding process. Furthermore, with the increase of granular size, the soil structure is not compact enough, and the cohesion between water and soil grains is extremely poor, which lead to the impact scope expanded of wet soil landslide disasters.

Numerical study of sheared mobile polydisperse sediment beds with a coupled lattice Boltzmann - discrete element method

2021 ◽  
Author(s):  
Christoph Rettinger ◽  
Sebastian Eibl ◽  
Ulrich Rüde ◽  
Bernhard Vowinckel
Keyword(s):  
Discrete Element Method ◽  
Lattice Boltzmann ◽  
Numerical Study ◽  
Experimental Studies ◽  
Discrete Element ◽  
Parallel Execution ◽  
Coupling Mechanism ◽  
Size Segregation ◽  
Minimum Diameter ◽  
Element Method

<p>With the increasing computational power of today's supercomputers, geometrically fully resolved simulations of particle-laden flows are becoming a viable alternative to laboratory experiments. Such simulations enable detailed investigations of transport phenomena in various multiphysics scenarios, such as the coupled interaction of sediment beds with a shearing fluid flow. There, the majority of available simulations as well as experimental studies focuses on setups of monodisperse particles. In reality, however, polydisperse configurations are much more common and feature unique effects like vertical size segregation.</p><p>In this talk, we will present numerical studies of mobile polydisperse sediment beds in a laminar shear flow, with a ratio of maximum to minimum diameter up to 10. The lattice Boltzmann method is applied to represent the fluid dynamics through and above the sediment bed efficiently. We model particle interactions by a discrete element method and explicitly account for lubrication forces. The fluid-particle coupling mechanism is based on the geometrically fully resolved momentum transfer between the fluid and the particulate phase. We will highlight algorithmic aspects and communication schemes essential for massively parallel execution.</p><p>Utilizing these capabilities allows us to achieve large-scale simulations with more than 26.000 densely-packed polydisperse particles interacting with the fluid. With this, we are able to reproduce effects like size segregation and to study the rheological behavior of such systems in great detail. We will evaluate and discuss the influence of polydispersity on these processes. These insights will be used to improve and extend existing macroscopic models.</p>

scholarly journals Validation of Particle Size Segregation of Sintered Ore during Flowing through Laboratory-scale Chute by Discrete Element Method

2008 ◽  
Vol 48 (12) ◽  
pp. 1696-1703 ◽  
Author(s):  
Hiroshi Mio ◽  
Satoshi Komatsuki ◽  
Masatoshi Akashi ◽  
Atsuko Shimosaka ◽  
Yoshiyuki Shirakawa ◽  
...  
Keyword(s):  
Particle Size ◽  
Discrete Element Method ◽  
Discrete Element ◽  
Laboratory Scale ◽  
Size Segregation ◽  
Element Method

Discrete element method modeling of non-spherical granular flow in rectangular hopper

2010 ◽  
Vol 49 (2) ◽  
pp. 151-158 ◽  
Author(s):  
He Tao ◽  
Baosheng Jin ◽  
Wenqi Zhong ◽  
Xiaofang Wang ◽  
Bing Ren ◽  
...  
Keyword(s):  
Discrete Element Method ◽  
Granular Flow ◽  
Discrete Element ◽  
Element Method

Effect of Bed Depth on Granular Flow and Homogenization in a Vertical Bladed Mixer via Discrete Element Method

2015 ◽  
Vol 38 (7) ◽  
pp. 1195-1202 ◽  
Author(s):  
Tomas Barczi ◽  
Tereza Travnickova ◽  
Jaromir Havlica ◽  
Martin Kohout
Keyword(s):  
Discrete Element Method ◽  
Granular Flow ◽  
Discrete Element ◽  
Element Method

Simulation of Failure of a Fixed Beam Subjected to Impact Load Using Quadrilateral Discrete Element Method

2012 ◽  
Author(s):  
Rajesh P. Nair ◽  
C. Lakshmana Rao
Keyword(s):  
Discrete Element Method ◽  
Impact Analysis ◽  
Mechanical Response ◽  
Impact Load ◽  
Discrete Element ◽  
Failure Criteria ◽  
Discrete Elements ◽  
The Impact ◽  
Fixed Beam ◽  
Element Method

Discrete Element Method (DEM) is an explicit numerical scheme to model the mechanical response of solid and particulate media. In our paper, we are introducing Quadrilateral Discrete Element Method (QDEM) for the simulation of the separation of elements in fixed beam subjected to impact load. QDEM results are compared with other DEM results available in literature. Impact loads include two cases: (a) a half sine wave and (b) a penetrator hitting the fixed beam. Separation criteria used for the discrete elements is maximum principal stress failure criteria. In QDEM, convergence study for the response of fixed beam is obtained using MATLAB platform. Validation of quadrilateral elements in fixed beam is being carried out by comparing the results with empirical formula available in literature for the impact analysis.

Predicting the drag coefficient of a granular flow using the discrete element method

2009 ◽  
Vol 2009 (06) ◽  
pp. P06012 ◽  
Author(s):  
Lionel Favier ◽  
Dominique Daudon ◽  
Frédéric-Victor Donzé ◽  
Jacky Mazars
Keyword(s):  
Discrete Element Method ◽  
Drag Coefficient ◽  
Granular Flow ◽  
Discrete Element ◽  
Element Method
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