The complete form of moment equations of stellar dynamics
The exact mathematical expression for an arbitrary nth-order stellar hydrodynamic equation is explicitly obtained depending on the central moments of the velocity distribution. In such a form the equations are physically meaningful, since they can be compared with the ordinary hy- drodynamic equatio...
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| Tipo de recurso: | informe técnico |
| Fecha de publicación: | 2007 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/1242 |
| Acceso en línea: | https://hdl.handle.net/2117/1242 |
| Access Level: | acceso abierto |
| Palabra clave: | Stellar dynamics Hydrodynamics Mathematical models hydrodynamics statistics methods: analytical stars: kinematics galaxies: kinematics and dynamics galaxies: statistics Hidrodinàmica -- Matemàtica Dinàmica estel·lar Classificació AMS::60 Probability theory and stochastic processes Classificació AMS::62 Statistics Classificació AMS::85 Astronomy and astrophysics Àrees temàtiques de la UPC::Matemàtiques i estadística::Equacions diferencials i integrals::Sistemes dinàmics Àrees temàtiques de la UPC::Física::Astronomia i astrofísica::Cosmologia i cosmogonia |
| Sumario: | The exact mathematical expression for an arbitrary nth-order stellar hydrodynamic equation is explicitly obtained depending on the central moments of the velocity distribution. In such a form the equations are physically meaningful, since they can be compared with the ordinary hy- drodynamic equations of compressible, viscous fluids. The equations are deduced without any particular assumptions about symmetries, steadi- ness, or particular kinematic behaviours, so that they can be used in their complete form, and for any order, in future works with improved observational data. Also, in order to work with a finite number of equa- tions and unknowns, which would provide a dynamic model for the stel- lar system, the nth-order equation is needed to investigate in a more general way the closure conditions, which may be expressed in terms of velocity distribution statistics, as it is shown in a case example. |
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