Turbulent-like velocity fluctuations in two-dimensional granular materials subject to cyclic shear

Soft Matter ◽  
2022 ◽  
Author(s):  
Aile Sun ◽  
Yinqiao Wang ◽  
Yangrui Chen ◽  
Jin Shang ◽  
Jie Zheng ◽  
...  
Keyword(s):  
Experimental Study ◽  
Granular Materials ◽  
Granular Matter ◽  
Two Dimensional ◽  
Friction Coefficients ◽  
Velocity Fluctuations ◽  
Cyclic Shear

We perform a systematic experimental study to investigate the velocity fluctuations in the two-dimensional granular matter of low and high friction coefficients subjected to cyclic shear of a range of...

Kinematics and statistics of dense, slow granular flow through vertical channels

2008 ◽  
Vol 610 ◽  
pp. 69-97 ◽  
Author(s):  
ANANDA K. S. ◽  
SUDHESHNA MOKA ◽  
PRABHU R. NOTT
Keyword(s):  
Granular Materials ◽  
Spatial Correlation ◽  
Deformation Rate ◽  
Three Dimensional ◽  
Thin Layers ◽  
Image Processing Technique ◽  
Plasticity Model ◽  
Two Dimensional ◽  
Velocity Fluctuations ◽  
Macroscopic Deformation

We have investigated the flow of dry granular materials through vertical channels in the regime of dense slow flow using video imaging of the particles adjacent to a transparent wall. Using an image processing technique based on particle tracking velocimetry, the video movies were analysed to obtain the velocities of individual particles. Experiments were conducted in two- and three-dimensional channels. In the latter, glass beads and mustard seeds were used as model granular materials, and their translational velocities were measured. In the former, aluminium disks with a dark diametral stripe were used and their translational velocities and spin were measured. Experiments in the three-dimensional channels were conducted for a range of the channel width W, and for smooth and rough sidewalls. As in earlier studies, we find that shearing takes place predominantly in thin layers adjacent to the walls, while the rest of the material appears to move as a plug. However, there are large velocity fluctuations even in the plug, where the macroscopic deformation rate is negligibly small. The thickness of the shear layer, scaled by the particle diameter dp, increases weakly with W/dp. The experimental data for the velocity field are in good agreement with the Cosserat plasticity model proposed recently. We also measured the mean spin of the particles in the two-dimensional channel, and its deviation from half the vorticity. There is a clear, measurable deviation, which too is in qualitative agreement with the Cosserat plasticity model. The statistics of particle velocity and spin fluctuations in the two-dimensional channel were analysed by determining their probability distribution function, and their spatial and temporal correlation. They were all found to be broadly similar to previous observations for three-dimensional channels, but some differences are evident. The spatial correlation of the velocity fluctuations are much stronger in the two-dimensional channel, implying a pronounced solid-like motion superimposed over an uncorrelated fluid-like motion. The strong spatial correlation over large distances has led us to propose a mechanism for the production of velocity fluctuations in the absence of a macroscopic deformation rate.

Theoretical and experimental study of fabrics developed by different shaped markers in two-dimensional simple shear

1983 ◽  
Vol S7-XXV (3) ◽  
pp. 319-326 ◽  
Author(s):  
Angel Fernandez ◽  
Jean-Louis Feybesse ◽  
Jean-Francois Mezure
Keyword(s):  
Experimental Study ◽  
Simple Shear ◽  
Two Dimensional

scholarly journals Investigation of Flows in Rectangular Diffusers With Inlet Flow Distortion

1982 ◽  
Author(s):  
M. M. Al-Mudhafar ◽  
M. Ilyas ◽  
F. S. Bhinder
Keyword(s):  
Experimental Study ◽  
Velocity Profiles ◽  
Pressure Recovery ◽  
Two Dimensional ◽  
Flow Distortion ◽  
Inlet Flow ◽  
Inlet Velocity ◽  
Inlet Distortion ◽  
Mach Numbers ◽  
Inlet Flow Distortion

The results of an experimental study on the influence of severely distorted velocity profiles on the performance of a straight two-dimensional diffuser are reported. The data cover entry Mach numbers ranging from 0.1 to 0.6 and several inlet distortion levels. The pressure recovery progressively deteriorates as the inlet velocity is distorted.

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