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Title: Dense inclined flows: Theory and experiments. Quarterly technical progress report, October 1, 1992--December 31, 1992

Abstract

Rapid, gravity-driven flows of granular materials down inclines pose a challenge to our understanding. Even in situations in which the flow is steady and two-dimensional, the details of how momentum and energy are balanced within the flow and at the bottom boundary are not well understood. Thus we have undertaken a research program integrating theory, computer simulation, and experiment that will focus on dense entry flows down inclines. Its goal is to understand the regime of inclined flow that involves a large, relatively passive mass of granular material moving above a narrow region of intensely sheared, colliding grains. The effort involves the development of theory informed by the results of simultaneous computer simulations and the construction, instrumentation, and use of an experimental facility in which the variables necessary to assess the success or failure of the theory can be measured. In the presetn reporting period, we have completed a series of experiments to measure the collision properties of various small particles. Results for 3mm glass beads are presented here. In addition, we have made progress in the design of a new sensor to measure simultaneously the particle volume fraction near the wall and the normal force of impact from individualmore » collisions. Finally, we have conducted additional simulations of the rapid granular flows of spheres interacting with a flat, frictional wall. The objective was to generate semi-empirical expressions for the boundary conditions imposed by the wall on the flow.« less

Publication Date:
Research Org.:
Cornell Univ., Ithaca, NY (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
10139543
Report Number(s):
DOE/PC/90183-T6
ON: DE93011452
DOE Contract Number:
AC22-91PC90183
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: [1992]
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; GRANULAR MATERIALS; SOLIDS FLOW; PROGRESS REPORT; COMPUTERIZED SIMULATION; GLASS; SHEAR; COLLISIONS; SPHERES; BOUNDARY CONDITIONS; 013000; TRANSPORT, HANDLING, AND STORAGE

Citation Formats

Not Available. Dense inclined flows: Theory and experiments. Quarterly technical progress report, October 1, 1992--December 31, 1992. United States: N. p., 1992. Web. doi:10.2172/10139543.
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Not Available. Dense inclined flows: Theory and experiments. Quarterly technical progress report, October 1, 1992--December 31, 1992. United States. doi:10.2172/10139543.
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Not Available. Thu . "Dense inclined flows: Theory and experiments. Quarterly technical progress report, October 1, 1992--December 31, 1992". United States. doi:10.2172/10139543. https://www.osti.gov/servlets/purl/10139543.
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@article{osti_10139543,
title = {Dense inclined flows: Theory and experiments. Quarterly technical progress report, October 1, 1992--December 31, 1992},
author = {Not Available},
abstractNote = {Rapid, gravity-driven flows of granular materials down inclines pose a challenge to our understanding. Even in situations in which the flow is steady and two-dimensional, the details of how momentum and energy are balanced within the flow and at the bottom boundary are not well understood. Thus we have undertaken a research program integrating theory, computer simulation, and experiment that will focus on dense entry flows down inclines. Its goal is to understand the regime of inclined flow that involves a large, relatively passive mass of granular material moving above a narrow region of intensely sheared, colliding grains. The effort involves the development of theory informed by the results of simultaneous computer simulations and the construction, instrumentation, and use of an experimental facility in which the variables necessary to assess the success or failure of the theory can be measured. In the presetn reporting period, we have completed a series of experiments to measure the collision properties of various small particles. Results for 3mm glass beads are presented here. In addition, we have made progress in the design of a new sensor to measure simultaneously the particle volume fraction near the wall and the normal force of impact from individual collisions. Finally, we have conducted additional simulations of the rapid granular flows of spheres interacting with a flat, frictional wall. The objective was to generate semi-empirical expressions for the boundary conditions imposed by the wall on the flow.},
doi = {10.2172/10139543},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Dec 31 00:00:00 EST 1992},
month = {Thu Dec 31 00:00:00 EST 1992}
}
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Technical Report:
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DOI:  10.2172/10139543
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  • ;
    Rapid, gravity-driven flows of granular materials down inclines pose a challenge to our understanding. Even in situations in which the flow is steady and two-dimensional, the details of how momentum and energy are balanced within the flow and at the bottom boundary are not well understood. Thus we have undertaken a research program integrating theory, computer simulation, and experiment that will focus on dense entry flows down inclines. The effort involves the development of theory informed by the results of simultaneous computer simulations and the construction, instrumentation, and use of an experimental facility in which the variables necessary to assessmore » the success or failure of the theory can be measured. In the present reporting period, we have continued a series of measurements in the chute facility with a flat, frictional boundary. At several inclinations between 15.5{degrees} and 20{degrees}, and at several gate openings for each angle, we have measured mass flow rate and mass holdup, as well as granular temperature and collision frequency at the bottom wall of the chute. By recording simultaneously the collisional normal stress at the bottom wall and the mass holdup above it, the experiments reveal the fraction of the weight of particles that is supported by direct impact.« less

  • ;
    Rapid, gravity-driven flows of granular materials down inclines pose a challenge; even in situations in which the flow is steady and two-dimensional, the balance of momentum and energy within the flow and at the bottom boundary are not well understood. A research program was undertaken integrating theory, computer simulation, and experiment that will focus on dense entry flows down inclines. The effort involves the development of theory informed by the results of simultaneous computer simulations and the construction, instrumentation, and use of an experimental facility in which the variables necessary to assess the success or failure of the theory canmore » be measured. In this period, we have improved the operations of the chute facility to permit a precise setting of its angle. We have also improved the microphone probe and collection vessel that records the mass holdup of particles. We have completed a series of measurements of the impact properties of acrylic and polystyrene spheres. Finally, we have interrogated our computer simulations in an effort to refine our theoretical predictions for the flux of fluctuating energy through a flat, frictional wall.« less

  • Rapid, gravity-driven flows of granular materials down inclines pose a challenge to our understanding. Even in situations in which the flow is steady and two-dimensional, the details of how momentum and energy are balanced within the flow and at the bottom boundary are not well understood. Thus we have undertaken a research program integrating theory, computer simulation, and experiment that will focus on dense entry flows down inclines. Its goal is to understand the regime of inclined flow that involves a large, relatively passive mass of granular material moving above a narrow region of intensely sheared, colliding grains. The effortmore » involves the development of theory informed by-the results of simultaneous computer simulations and the construction, instrumentation, and use of an experimental facility in which the variables necessary to assess the success or failure of the theory can be measured. In the present reporting period, we have completed a new series of experiments to measure the collision properties of acetate and glass particles involved in binary collisions or impacting on a flat surface. Results for 3mm glass beads and 6mm acetate spheres are presented here. In addition, we have finalized the desip of a new sensor to measure simultaneously the particle volume fraction near the wall and the normal force of impact from individual collisions. Finally, we have completed our numerical simulations of the rapid granular flows of spheres interacting with a flat, frictional wall.« less

  • Rapid, gravity-driven flows of granular materials down inclines pose a challenge to the understanding of solids flow. Even in situations in which the flow is steady and two-dimensional, the details of how momentum and energy are balanced within the flow and at the bottom boundary are not well understood. Thus the authors have undertaken a research program integrating theory, computer simulation, and experiment that will focus on dense entry flows down inclines. The effort involves the development of theory informed by the results of simultaneous computer simulations and the construction, instrumentation, and use of an experimental facility in which themore » variables necessary to assess the success or failure of the theory can be measured. In the present reporting period, the authors began a series of measurements in the chute facility with a bumpy boundary constructed using random two-dimensional packings of 1 mm glass spheres. At the inclination of 19{degree} and at several gate openings, they measured mass flow rate and mass holdup, as well as granular temperature and collision frequency at the bottom wall of the chute. By recording simultaneously the collisional normal stress at the bottom wall and the mass holdup above it, the experiments revealed that, unlike the flat boundary, only a small fraction of the weight of particles is supported by direct impact. The authors have also completed measurements of the impact properties for several binary collisions of nearly spherical particles used in this and other projects. A table summarizes the data obtained.« less

  • Rapid, gravity-driven flows of granular materials down inclines pose a challenge to our understanding. Even in situations in which the flow is steady and two-dimensional, the details of how momentum and energy are balanced within the flow and at the bottom boundary are not well understood. Thus we have undertaken a research program integrating theory, computer simulation, and experiment that will focus on dense entry flows down inclines. The effort involves the development of theory informed by the results of simultaneous computer simulations and the construction, instrumentation, and use of an experimental facility in which the variables necessary to assessmore » the success or failure of the theory can be measured. In the present reporting period, we have completed the experiments with the bumpy base consisting of random two-dimensional packings of l nun glass spheres; we have derived boundary conditions for a bumpy frictionless boundary for other than small slip velocities; and we have made numerical studies of hydraulic equations using a simple Lagrangian code that we have developed. We are now in the process of writing the final report and a journal article summarizing our findings.« less