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| Titel |
Viscous heating in fluids with temperature-dependent viscosity: implications for magma flows |
| VerfasserIn |
A. Costa, G. Macedonio |
| 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 ; 10, no. 6 ; Nr. 10, no. 6, S.545-555 |
| Datensatznummer |
250008210
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| Publikation (Nr.) |
 copernicus.org/npg-10-545-2003.pdf |
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| Zusammenfassung |
| Viscous heating
plays an important role in the dynamics of fluids with strongly
temperature-dependent viscosity because of the coupling between the energy
and momentum equations. The heat generated by viscous friction produces a
local temperature increase near the tube walls with a consequent decrease
of the viscosity which may dramatically change the temperature and
velocity profiles. These processes are mainly controlled by the Peclét
number, the Nahme number, the flow rate and the thermal boundary
conditions. The problem of viscous heating in fluids was investigated in
the past for its practical interest in the polymer industry, and was
invoked to explain some rheological behaviours of silicate melts, but was
not completely applied to study magma flows. In this paper we focus on the
thermal and mechanical effects caused by viscous heating in tubes of
finite lengths. We find that in magma flows at high Nahme number and
typical flow rates, viscous heating is responsible for the evolution from
Poiseuille flow, with a uniform temperature distribution at the inlet, to
a plug flow with a hotter layer near the walls. When the temperature
gradients induced by viscous heating are very pronounced, local
instabilities may occur and the triggering of secondary flows is possible.
For completeness, this paper also describes magma flow in infinitely long
tubes both at steady state and in transient phase. |
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