scholarly journals Effect of particle shape on particle breakage inside rotating cylinders

2021 ◽  
Vol 249 ◽  
pp. 07002
Author(s):  
Luisa Fernanda Orozco ◽  
Jean-Yves Delenne ◽  
Philippe Sornay ◽  
Farhang Radjai
Keyword(s):  
Free Surface ◽  
Particle Shape ◽  
Surface Profile ◽  
Particle Breakage ◽  
Rotating Cylinders ◽  
Free Surface Profile ◽  
Dynamics Simulations ◽  
Polygonal Particle ◽  
Particle Shapes ◽  
Flow Particle

We study the influence of particle shape on the evolution of particle breakage process taking place inside rotating cylinders. Extensive particle dynamics simulations taking into account the dynamics of the granular flow, particle breakage, and polygonal particle shapes were carried out. We find that the rate of particle breakage is faster in samples composed of initially rounder particles. The analysis of the active flowing layer thickness suggests that for samples composed of rounder particles a relatively lower dilatancy and higher connectivity lead to a less curved free surface profile. As a result, rounder particles rolling down the free surface have a higher mobility and thus higher velocities. In consequence, the faster breakage observed for rounder initial particles is due to the larger particles kinetic energy at the toe of the flow.

scholarly journals Dam-Break Flows: Comparison between Flow-3D, MIKE 3 FM, and Analytical Solutions with Experimental Data

2018 ◽  
Vol 8 (12) ◽  
pp. 2456 ◽  
Author(s):  
Hui Hu ◽  
Jianfeng Zhang ◽  
Tao Li
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Analytical Solution ◽  
Water Depth ◽  
3D Model ◽  
Real Life ◽  
Surface Profile ◽  
Dam Break ◽  
Computational Time ◽  
Free Surface Profile

The objective of this study was to evaluate the applicability of a flow model with different numbers of spatial dimensions in a hydraulic features solution, with parameters such a free surface profile, water depth variations, and averaged velocity evolution in a dam-break under dry and wet bed conditions with different tailwater depths. Two similar three-dimensional (3D) hydrodynamic models (Flow-3D and MIKE 3 FM) were studied in a dam-break simulation by performing a comparison with published experimental data and the one-dimensional (1D) analytical solution. The results indicate that the Flow-3D model better captures the free surface profile of wavefronts for dry and wet beds than other methods. The MIKE 3 FM model also replicated the free surface profiles well, but it underestimated them during the initial stage under wet-bed conditions. However, it provided a better approach to the measurements over time. Measured and simulated water depth variations and velocity variations demonstrate that both of the 3D models predict the dam-break flow with a reasonable estimation and a root mean square error (RMSE) lower than 0.04, while the MIKE 3 FM had a small memory footprint and the computational time of this model was 24 times faster than that of the Flow-3D. Therefore, the MIKE 3 FM model is recommended for computations involving real-life dam-break problems in large domains, leaving the Flow-3D model for fine calculations in which knowledge of the 3D flow structure is required. The 1D analytical solution was only effective for the dam-break wave propagations along the initially dry bed, and its applicability was fairly limited.

scholarly journals Experimental Characterization of the Hydraulic Jump Profile and Velocity Distribution in a Stilling Basin Physical Model

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1758
Author(s):  
Juan Macián-Pérez ◽  
Francisco Vallés-Morán ◽  
Santiago Sánchez-Gómez ◽  
Marco De-Rossi-Estrada ◽  
Rafael García-Bartual
Keyword(s):  
Free Surface ◽  
Energy Dissipation ◽  
Velocity Distribution ◽  
Physical Model ◽  
Hydraulic Jump ◽  
Surface Profile ◽  
Air Entrainment ◽  
Stilling Basin ◽  
Free Surface Profile ◽  
Stilling Basins

The study of the hydraulic jump developed in stilling basins is complex to a high degree due to the intense velocity and pressure fluctuations and the significant air entrainment. It is this complexity, bound to the practical interest in stilling basins for energy dissipation purposes, which brings the importance of physical modeling into the spotlight. However, despite the importance of stilling basins in engineering, bibliographic studies have traditionally focused on the classical hydraulic jump. Therefore, the objective of this research was to study the characteristics of the hydraulic jump in a typified USBR II stilling basin, through a physical model. The free surface profile and the velocity distribution of the hydraulic jump developed within this structure were analyzed in the model. To this end, an experimental campaign was carried out, assessing the performance of both, innovative techniques such as the time-of-flight camera and traditional instrumentation like the Pitot tube. The results showed a satisfactory representation of the free surface profile and the velocity distribution, despite some discussed limitations. Furthermore, the instrumentation employed revealed the important influence of the energy dissipation devices on the flow properties. In particular, relevant differences were found for the hydraulic jump shape and the maximum velocity positions within the measured vertical profiles, when compared to classical hydraulic jumps.

scholarly journals The effect of particle shape on the deformation and stress reduction of a gravel soil due to wetting

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Reza Mahinroosta ◽  
Vahid Oshtaghi
Keyword(s):  
Particle Size ◽  
Shear Stress ◽  
Particle Size Distribution ◽  
Normal Stress ◽  
Size Distribution ◽  
Stress Reduction ◽  
Particle Shape ◽  
Particle Breakage ◽  
Direct Shear ◽  
Particle Shapes

AbstractThis paper investigates the effect of particle shape on the stress reduction and collapse deformation of gravelly soil using a medium-scale direct shear test apparatus under different relative densities, normal stress, and shear stress levels. A new method based on the Micro-Deval test was introduced to produce sub-angular particles from angular particles. Therefore, two series of soil specimens were obtained with the same rock origin, particle size distribution, and relative density but different particle shapes. In addition to traditional direct shear tests on dry and wet specimens, a specific test procedure was applied to explore the stress reduction and collapse of soil specimens due to wetting. The results of the tests, including shear stress–shear displacement and vertical displacement-shear displacement, were compared. The results showed that the stress reduction and settlement due to wetting increased with vertical and shear stress levels in both types of particle shapes, with higher values in angular particle shapes. The particle breakage of the soil specimens was also studied quantitatively using the change in the particle size distribution before and after the test. It was shown that the wetting of the samples had more impact on the particle breakage in angular gravel than sub-angular gravel, which increased linearly with the normal stress.

Measurements of the time-varying free-surface profile across the swash zone obtained using an industrial LIDAR

2010 ◽  
Vol 57 (11-12) ◽  
pp. 1059-1065 ◽  
Author(s):  
C.E. Blenkinsopp ◽  
M.A. Mole ◽  
I.L. Turner ◽  
W.L. Peirson
Keyword(s):  
Free Surface ◽  
Surface Profile ◽  
Time Varying ◽  
Swash Zone ◽  
Free Surface Profile

Classical hydraulic jump: free surface profile

1993 ◽  
Vol 20 (3) ◽  
pp. 536-539 ◽  
Author(s):  
Willi H. Hager
Keyword(s):  
Free Surface ◽  
Channel Flow ◽  
Hydraulic Jump ◽  
Simple Formula ◽  
Open Channel ◽  
Surface Profile ◽  
Novel Approach ◽  
Flow Hydraulics ◽  
Channel Surface ◽  
Free Surface Profile

Based on a large number of experiments, a simple formula is developed for the time-averaged free surface profile of a classical hydraulic jump. This novel approach is based on the length of the roller. The resulting surface profile fits the data well for usual inflow Froude numbers in the range of 2 to 10. Key words: backwater, channel flow, hydraulics, open channel, surface profile.

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