Rigid intruder inside a two-dimensional dense granular flow: Drag force and cavity formation

2013 ◽  
Vol 87 (3) ◽  
Author(s):  
Evelyne Kolb ◽  
Pierre Cixous ◽  
Niels Gaudouen ◽  
Thierry Darnige
Keyword(s):  
Drag Force ◽  
Granular Flow ◽  
Cavity Formation ◽  
Two Dimensional ◽  
Dense Granular Flow ◽  
Flow Drag

Numerical simulations of dense granular flow in a two-dimensional channel: The role of exit position

2018 ◽  
Vol 27 (12) ◽  
pp. 124704
Author(s):  
Tingwei Wang ◽  
Xin Li ◽  
Qianqian Wu ◽  
Tengfei Jiao ◽  
Xingyi Liu ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Granular Flow ◽  
Two Dimensional ◽  
Dense Granular Flow

A Convex Complementarity Approach for Simulating Large Granular Flows

2010 ◽  
Vol 5 (3) ◽  
Author(s):  
Alessandro Tasora ◽  
Mihai Anitescu
Keyword(s):  
Granular Flow ◽  
Complementarity Problems ◽  
Particle Interaction ◽  
Granular Flows ◽  
Rigid Bodies ◽  
Integration Time ◽  
Frictional Contacts ◽  
Physical Experiments ◽  
Dense Granular Flow ◽  
Number Of Particles

Aiming at the simulation of dense granular flows, we propose and test a numerical method based on successive convex complementarity problems. This approach originates from a multibody description of the granular flow: all the particles are simulated as rigid bodies with arbitrary shapes and frictional contacts. Unlike the discrete element method (DEM), the proposed approach does not require small integration time steps typical of stiff particle interaction; this fact, together with the development of optimized algorithms that can run also on parallel computing architectures, allows an efficient application of the proposed methodology to granular flows with a large number of particles. We present an application to the analysis of the refueling flow in pebble-bed nuclear reactors. Extensive validation of our method against both DEM and physical experiments results indicates that essential collective characteristics of dense granular flow are accurately predicted.

Numerical Analysis of Bridge Expansion-Induced Rail Deformation of Ballast Truck

2014 ◽  
Vol 580-583 ◽  
pp. 3208-3214 ◽  
Author(s):  
Zhen Wei Xiong ◽  
Xin Ling Liang ◽  
Xian Xing Dai ◽  
Ping Wang
Keyword(s):  
Granular Flow ◽  
Element Model ◽  
Discrete Element Model ◽  
Board Structure ◽  
Vertical Deformation ◽  
Two Dimensional ◽  
Running Safety ◽  
Bridge Plate ◽  
Ballast Track ◽  
The Relationship

when the ballast track stretch with the bridge, ballast which is near expansion joint will move confusedly. As a result, rail produced vertical deformation. The deformation will affect the running safety and comfortability of train. At present, there are two kinds of treatments which are cover board structure and baffle structure to deal ballast’s movement. Aiming at the different modes of stretching when the two kinds of structures and different arrangement condition of bridge plate are applied, the rail-sleeper-ballast discrete element model is developed by the method of two-dimensional granular flow. The relationship between rail deformation and bridge expansion is analyzed on the foundation of the model. Results show as flows: when bridge extends or shortens, rail always produced upwarp deformation. Bridge plate should arrange asymmetrically. Like this, the rail deformation decrease by 40%. And adopting the baffle structure can effectively reduce the influence of bridge expansion in ballast truck.

On characteristics of the water-particle velocity in a plunging breaker

1983 ◽  
Vol 126 ◽  
pp. 251-268 ◽  
Author(s):  
Takeo Nakagawa
Keyword(s):  
Wave Energy ◽  
Wave Breaking ◽  
Separate Flow ◽  
Transverse Flow ◽  
Two Dimensional ◽  
Frequency Range ◽  
Flow Component ◽  
Flow Components ◽  
Flow Drag ◽  
Plunging Breaker

Three velocity components of water particles in a plunging breaker over a horizontal step on the bed of a two-dimensional laboratory wave tank have been determined simultaneously by means of an elaborate flowmeter that measures the flow drag on three ‘tension threads’, with each recording a separate flow component.It is found that all three of the r.m.s. values in the plunging breaker become maximum at x/L ≈ 0·7, where x is the distance from the breaking point to the shore and L is the wavelength. It is found that both the velocity and r.m.s. values of the transverse flow component generated by the shoaling and wave breaking become comparable to those of the other two flow components.On the basis of spectral analyses it is found that major wave frequencies in both the longitudinal and vertical flow components of the original two-dimensional wave survive even after experiencing relatively strong shoaling and wave breaking, and part of the original wave energy is transferred to the transverse flow component and is located at these major frequencies. It is found that the majority of the higher-harmonic-frequency components (or turbulent fluctuations) are generated in the shoaling process and that the wave breaking provides a relatively minor contribution to the generation. Finally, it is found that, through the shoaling and wave breaking, the original wave energy is transported to a frequency range lower than the primary wave frequency (negative cascade), as well as to the higher frequency range (positive cascade) in each flow component.

scholarly journals Effect of boundary on the two-dimensional inclined channel for a dilute granular flow distribution

2004 ◽  
Vol 53 (10) ◽  
pp. 3389
Author(s):  
Zhou Ying ◽  
Bao De-Song ◽  
Zhang Xun-Sheng ◽  
Lei Zhe-Min ◽  
Hu Guo-Qi ◽  
...  
Keyword(s):  
Granular Flow ◽  
Flow Distribution ◽  
Two Dimensional ◽  
Inclined Channel

Experimental and computational studies of dense granular flow: Transition from quasi-static to intermediate regime in a Couette shear device

2012 ◽  
Vol 220 ◽  
pp. 7-14 ◽  
Author(s):  
V. Vidyapati ◽  
M. Kheiripour Langroudi ◽  
J. Sun ◽  
S. Sundaresan ◽  
G.I. Tardos ◽  
...  
Keyword(s):  
Granular Flow ◽  
Computational Studies ◽  
Flow Transition ◽  
Intermediate Regime ◽  
Dense Granular Flow

Experimental Study on the Influence of Hull Spacing on Hard-Chine Catamaran Motions

2001 ◽  
Vol 45 (03) ◽  
pp. 216-227
Author(s):  
R. Centeno ◽  
K. S. Varyani ◽  
C. Guedes Soares
Keyword(s):  
Experimental Study ◽  
Cross Flow ◽  
Experimental Program ◽  
Two Dimensional ◽  
Regular Waves ◽  
Viscous Forces ◽  
Motion Responses ◽  
Resonance Frequencies ◽  
Flow Drag ◽  
Wave Induced

An experimental program was performed with hard-chine catamaran models in regular waves. The distance between the demi-hulls of the models was changed to assess its effects on the wave-induced motions. The results allowed the study of some aspects related to catamaran motions, like the interference between the hulls and resonance frequencies. The experimental results are compared with calculations performed with a recently developed code based on a two-dimensional potential flow theory in which viscous forces are included through a cross-flow drag approach. The effect of the hull distance in the heave and pitch motion responses and the importance of the viscous forces in such hull configurations are shown.

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