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| Titel |
Energy considerations in accelerating rapid shear granular flows |
| VerfasserIn |
S. P. Pudasaini, B. Domnik |
| 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 ; 16, no. 3 ; Nr. 16, no. 3 (2009-05-20), S.399-407 |
| Datensatznummer |
250013190
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| Publikation (Nr.) |
 copernicus.org/npg-16-399-2009.pdf |
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| Zusammenfassung |
| We present a complete expression for the total energy associated with a rapid
frictional granular shear flow down an inclined surface. This expression
reduces to the often used energy for a non-accelerating flow of an isotropic,
ideal fluid in a horizontal channel, or to the energy for a vertically
falling mass. We utilize thickness-averaged mass and momentum conservation
laws written in a slope-defined coordinate system. Both the enhanced gravity
and friction are taken into account in addition to the bulk motion and
deformation. The total energy of the flow at a given spatial position and
time is defined as the sum of four energy components: the kinetic energy,
gravity, pressure and the friction energy. Total energy is conserved for
stationary flow, but for non-stationary flow the non-conservative force
induced by the free-surface gradient means that energy is not conserved.
Simulations and experimental results are used to sketch the total energy of
non-stationary flows. Comparison between the total energy and the sum of the
kinetic and pressure energy shows that the contribution due to gravity
acceleration and frictional resistance can be of the same order of magnitude,
and that the geometric deformation plays an important role in the total
energy budget of the cascading mass. Relative importance of the different
constituents in the total energy expression is explored. We also introduce an
extended Froude number that takes into account the apparent potential energy
induced by gravity and pressure. |
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