scholarly journals Shear Band Characterization of Clayey Soils with Particle Image Velocimetry

2020 ◽  
Vol 10 (3) ◽  
pp. 1139
Author(s):  
Kwak ◽  
Park ◽  
Kim ◽  
Chung ◽  
Baek
Keyword(s):  
Particle Image Velocimetry ◽  
Spatial Distribution ◽  
Shear Band ◽  
Particle Image ◽  
Shear Bands ◽  
Side Wall ◽  
Failure Behavior ◽  
Clayey Soils ◽  
Initial State ◽  
Image Velocimetry

Identifying the spatial distribution of deformation and shear band characteristics is important for accurately modeling soil behavior and ensuring the safety of nearby geotechnical structures. However, most research on the shear behavior of soils has focused on granular soil and clay-rich rocks, with little focus on clayey soil, and the entire shearing process from the initial state to failure has not been observed. This study evaluated the spatial distribution and evolution of deformation in clayey soils from the initial state to the post-failure state and the shear band characteristics. Plane strain tests were performed on normally consolidated and over-consolidated clay specimens, and digital images were captured through a transparent side wall for particle image velocimetry (PIV) analysis. PIV was performed to evaluate the displacement and deformation of soil particles. The results show that the shear-strain behaviors of two clays during the shearing process could be divided into four stages: initial, peak, softening, and steady state. Shear bands were observed to form in the softening stage, and the shear band slopes were compared to values in the literature. These results can be used to characterize shear bands in clay as well as predict failure behavior and guide reinforcement at actual sites with soft ground.

Experimental Study of Turbulent Transport in Non-Isothermal Oscillating Grids Turbulence Using Particle Image Velocimetry

2003 ◽  
Author(s):  
Alexander Eidelman ◽  
Tov Elperin ◽  
Nathan Kleeorin ◽  
Alexander Krein ◽  
Igor Rogachevskii ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Spatial Distribution ◽  
Temperature Gradient ◽  
Thermal Diffusion ◽  
Particle Image ◽  
Turbulent Transport ◽  
Mean Temperature ◽  
Image Velocimetry ◽  
Oscillating Grids ◽  
The Mean

An oscillating grids turbulence generator was constructed for studies of a new effect associated with turbulent transport of inertial particles — turbulent thermal diffusion. This phenomenon was predicted theoretically in Phys. Rev. Lett. 76, 224 (1996) and has been detected experimentally in oscillating grids turbulence with an imposed mean temperature gradient in air flow. This effect implies an additional mean flux of particles in the direction opposite to the mean temperature gradient and results in formation of large-scale inhomogeneities in the spatial distribution of particles. We used Particle Image Velocimetry to determine the turbulent velocity field and an Image Processing Technique to determine the spatial distribution of particles. Velocity distributions were measured in the flow generated with one and two grids in the Oscillating Grids Turbulence Generators at RWTH (Aachen) and BGU (Beer-Sheva). Analysis of the intensity of laser light Mie scattering by particles showed that they are accumulated in the vicinity of the minimum of the mean temperature of the surrounding fluid. The latter finding confirms the existence of the effect of turbulent thermal diffusion predicted theoretically.

Steady and Pulsating Turbulent Flows in Complex Pipe Geometries

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Simone Colonia ◽  
Giovanni P. Romano
Keyword(s):  
Reynolds Number ◽  
Particle Image Velocimetry ◽  
Spatial Distribution ◽  
Turbulent Flows ◽  
Relative Intensity ◽  
Particle Image ◽  
Stress Fields ◽  
Straight Pipe ◽  
Pipe Flows ◽  
Image Velocimetry

In this paper, measurements of velocity and stress fields in rigid pipes are performed by means of planar particle image velocimetry (PIV). The attention is focused onto the effect of Reynolds number and of continuous or pulsating flows by investigating pipe geometries ranging from the straight pipe to the reduced section and bifurcated ones. The obtained results show that, in the tested range, the effect of Reynolds number is limited for straight and reduced section pipes, while significant for the bifurcated one. Independently of Reynolds number, different geometries and forcing (continuous or pulsed) produce strong variations in intensity and spatial distribution of velocity and stress fields. Considering the latter, the contribution of viscous and turbulent stresses are measured separately and compared. Indeed turbulent stresses are always larger than the viscous ones, but the relative intensity is highly variable as also the spatial distribution of maxima and minima. Specifically, in the pulsating flows, this distribution is phase-dependent reflecting the oscillations of regions of flow separation which form especially in reduced section and bifurcated pipes. These results are useful for all engineering applications in which turbulent pipe flows are involved.

Multiwavelets and Particle Image Velocimetry methods

1999 ◽  
Author(s):  
Andrew Kurdila ◽  
Othon Rediniotis ◽  
Thomas Strganac ◽  
Jeonghwan Ko
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Image Velocimetry
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