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New Insight into Pseudo-Thermal Convection in Vibrofluidised Granular Systems.
C R K Windows-Yule1,2,3, E Lanchester4, D Madkins4
1School of Chemical Engineering, The University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK. windowsyule@gmail.com.
Scientific Reports
|August 29, 2018
Summary
This study reveals how system geometry and material properties control granular convection. Energy flux at system boundaries, not wall effects, predominantly dictates convective motion dynamics in vibrofluidised granular assemblies.
Area of Science:
- Physics
- Granular Mechanics
- Fluid Dynamics
Background:
- Granular materials exhibit complex behaviors when subjected to vibration.
- Understanding convective patterns is crucial for controlling granular flows.
Purpose of the Study:
- To investigate the influence of geometric and elastic properties on convective behaviors in vibrofluidised granular assemblies.
- To identify and characterize novel convection-inducing mechanisms.
- To establish criteria for predicting dominant convection mechanisms and system dynamics.
Main Methods:
- Combined experimental positron emission particle tracking (PEPT) and numerical simulations.
- Utilized a novel 'modular' system geometry for parameter space exploration.
- Analyzed a broad, multi-dimensional parameter space encompassing geometric, elastic, and motion properties.
Main Results:
- Discovered previously undocumented convection-inducing mechanisms.
- Demonstrated methods to manipulate granular convection (induce, suppress, invert).
- Showed that energy flux at lateral boundaries, not wall effects, predominantly determines convective motion direction and strength.
Conclusions:
- Pseudo-thermal granular convection is primarily a collective phenomenon.
- System geometry and energy flux at boundaries are key determinants of granular convection.
- Established predictive criteria for granular convection dynamics based on system properties.
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