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| Titel |
Granular flow in equilibrium with the bottom: experimental analysis and theoretical prediction |
| VerfasserIn |
B. Zanuttigh, A. Lamberti |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 9, no. 3/4 ; Nr. 9, no. 3/4, S.207-220 |
| Datensatznummer |
250006538
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| Publikation (Nr.) |
 copernicus.org/npg-9-207-2002.pdf |
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| Zusammenfassung |
| The paper presents
measurements performed on the granular flow that develops in a drum
partially filled with sand grains and rotating at various speeds. The aims
of the paper are: to provide experimental evidence and measurements on
grain flow in a drum; to compare theoretical and experimental velocity
profiles; to point out discrepancies among theory and experiments. Velocity and "temperature" profiles were
obtained with a Laser Doppler Anemometer (LDA) in the mid-section of the
stream, where the flow is usually uniform; image analysis and visual
observations of the flow were also carried out to evaluate the local
slope, the depths of the characteristic flow regions and the concentration
of the granular material. A semi-empirical relation that fits the
experimental velocity profiles is presented and compared with Takahashi's
velocity distributions for rigid and erodible bed. As proven by the
distributions of free surface elevation, velocity, volumetric
concentration and grain size across the drum, the three-dimensional nature
of the flow field is not negligible. By increasing the drum rotation speed, in correspondence
with critical and supercritical flows, changes in the flow regime are
observed with formation of quasi-stationary surface waves. Wave
development is described by analysing the extension and form of the
experimental and theoretical velocity profiles. Wave effects on
measurements are quantified and checked comparing the free-surface
velocity-discharge relation obtained from experiments and from Takahashi's
model for erodible bed. |
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