Speeds of Propagation in Classical and Relativistic Extended Thermodynamics
The Navier-Stokes-Fourier theory of viscous, heat-conducting fluids provides parabolic equations and thus predicts infinite pulse speeds. Naturally this feature has disqualified the theory for relativistic thermodynamics which must insist on finite speeds and, moreover, on speeds smaller than $c$. T...
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| Format: | Article |
| Language: | English |
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SpringerOpen
1999-01-01
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| Series: | Living Reviews in Relativity |
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| Online Access: | http://www.livingreviews.org/lrr-1999-1 |
| _version_ | 1819158553177358336 |
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| author | Müller Ingo |
| author_facet | Müller Ingo |
| author_sort | Müller Ingo |
| collection | DOAJ |
| description | The Navier-Stokes-Fourier theory of viscous, heat-conducting fluids provides parabolic equations and thus predicts infinite pulse speeds. Naturally this feature has disqualified the theory for relativistic thermodynamics which must insist on finite speeds and, moreover, on speeds smaller than $c$. The attempts at a remedy have proved heuristically important for a new systematic type of thermodynamics: Extended thermodynamics. That new theory has symmetric hyperbolic field equations and thus it provides finite pulse speeds. Extended thermodynamics is a whole hierarchy of theories with an increasing number of fields when gradients and rates of thermodynamic processes become steeper and faster. The first stage in this hierarchy is the 14-field theory which may already be a useful tool for the relativist in many applications. The 14 fields -- and further fields -- are conveniently chosen from the moments of the kinetic theory of gases. The hierarchy is complete only when the number of fields tends to infinity. In that case the pulse speed of non-relativistic extended thermodynamics tends to infinity while the pulse speed of relativistic extended thermodynamics tends to $c$, the speed of light. In extended thermodynamics symmetric hyperbolicity -- and finite speeds -- are implied by the concavity of the entropy density. This is still true in relativistic thermodynamics for a privileged entropy density which is the entropy density of the rest frame for non-degenerate gases. |
| first_indexed | 2024-12-22T16:26:29Z |
| format | Article |
| id | doaj.art-3622c5ebb1a7441aa72ea41ed905790c |
| institution | Directory Open Access Journal |
| issn | 1433-8351 |
| language | English |
| last_indexed | 2024-12-22T16:26:29Z |
| publishDate | 1999-01-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Living Reviews in Relativity |
| spelling | doaj.art-3622c5ebb1a7441aa72ea41ed905790c2022-12-21T18:20:08ZengSpringerOpenLiving Reviews in Relativity1433-83511999-01-0121Speeds of Propagation in Classical and Relativistic Extended ThermodynamicsMüller IngoThe Navier-Stokes-Fourier theory of viscous, heat-conducting fluids provides parabolic equations and thus predicts infinite pulse speeds. Naturally this feature has disqualified the theory for relativistic thermodynamics which must insist on finite speeds and, moreover, on speeds smaller than $c$. The attempts at a remedy have proved heuristically important for a new systematic type of thermodynamics: Extended thermodynamics. That new theory has symmetric hyperbolic field equations and thus it provides finite pulse speeds. Extended thermodynamics is a whole hierarchy of theories with an increasing number of fields when gradients and rates of thermodynamic processes become steeper and faster. The first stage in this hierarchy is the 14-field theory which may already be a useful tool for the relativist in many applications. The 14 fields -- and further fields -- are conveniently chosen from the moments of the kinetic theory of gases. The hierarchy is complete only when the number of fields tends to infinity. In that case the pulse speed of non-relativistic extended thermodynamics tends to infinity while the pulse speed of relativistic extended thermodynamics tends to $c$, the speed of light. In extended thermodynamics symmetric hyperbolicity -- and finite speeds -- are implied by the concavity of the entropy density. This is still true in relativistic thermodynamics for a privileged entropy density which is the entropy density of the rest frame for non-degenerate gases.http://www.livingreviews.org/lrr-1999-1Mathematical Relativity |
| spellingShingle | Müller Ingo Speeds of Propagation in Classical and Relativistic Extended Thermodynamics Living Reviews in Relativity Mathematical Relativity |
| title | Speeds of Propagation in Classical and Relativistic Extended Thermodynamics |
| title_full | Speeds of Propagation in Classical and Relativistic Extended Thermodynamics |
| title_fullStr | Speeds of Propagation in Classical and Relativistic Extended Thermodynamics |
| title_full_unstemmed | Speeds of Propagation in Classical and Relativistic Extended Thermodynamics |
| title_short | Speeds of Propagation in Classical and Relativistic Extended Thermodynamics |
| title_sort | speeds of propagation in classical and relativistic extended thermodynamics |
| topic | Mathematical Relativity |
| url | http://www.livingreviews.org/lrr-1999-1 |
| work_keys_str_mv | AT mulleringo speedsofpropagationinclassicalandrelativisticextendedthermodynamics |