Thermodynamics of Fluid Elements in the Context of Turbulent Isothermal Self-Gravitating Molecular Clouds
In the present work, we suggest a new approach for studying the equilibrium states of an hydrodynamic isothermal turbulent self-gravitating system as a statistical model for a molecular cloud. The main hypothesis is that the local turbulent motion of the fluid elements is purely chaotic and can be r...
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2025-06-01
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| author | Sava Donkov Ivan Zh. Stefanov Valentin Kopchev |
| author_facet | Sava Donkov Ivan Zh. Stefanov Valentin Kopchev |
| author_sort | Sava Donkov |
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| description | In the present work, we suggest a new approach for studying the equilibrium states of an hydrodynamic isothermal turbulent self-gravitating system as a statistical model for a molecular cloud. The main hypothesis is that the local turbulent motion of the fluid elements is purely chaotic and can be regarded as a perfect gas. Then, the turbulent kinetic energy per fluid element can be substituted for the temperature of the chaotic motion of the fluid elements. Using this, we write down effective formulae for the internal and total the energy and for the first principal of thermodynamics. Then, we obtain expressions for the entropy, the free energy, and the Gibbs potential. Searching for equilibrium states, we explore two possible systems: the canonical ensemble and the grand canonical ensemble. Studying the former, we conclude that there is no extrema for the free energy. Through the latter system, we obtain a minimum of the Gibbs potential when the macro-temperature and pressure of the cloud are equal to those of the surrounding medium. This minimum corresponds to a possible stable local equilibrium state of our system. |
| format | Article |
| id | doaj-art-c8691a730c1d44d3a5cd464fc892fc6e |
| institution | Kabale University |
| issn | 2218-1997 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | MDPI AG |
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| series | Universe |
| spelling | doaj-art-c8691a730c1d44d3a5cd464fc892fc6e2025-08-20T03:32:33ZengMDPI AGUniverse2218-19972025-06-0111618410.3390/universe11060184Thermodynamics of Fluid Elements in the Context of Turbulent Isothermal Self-Gravitating Molecular CloudsSava Donkov0Ivan Zh. Stefanov1Valentin Kopchev2Institute of Astronomy and NAO, Bulgarian Academy of Sciences, 72 Tzarigradsko Chausee Blvd., 1784 Sofia, BulgariaDepartment of Applied Physics, Faculty of Applied Mathematics, Technical University-Sofia, 8 Kliment Ohridski Blvd., 1000 Sofia, BulgariaDepartment of Applied Physics, Faculty of Applied Mathematics, Technical University-Sofia, 8 Kliment Ohridski Blvd., 1000 Sofia, BulgariaIn the present work, we suggest a new approach for studying the equilibrium states of an hydrodynamic isothermal turbulent self-gravitating system as a statistical model for a molecular cloud. The main hypothesis is that the local turbulent motion of the fluid elements is purely chaotic and can be regarded as a perfect gas. Then, the turbulent kinetic energy per fluid element can be substituted for the temperature of the chaotic motion of the fluid elements. Using this, we write down effective formulae for the internal and total the energy and for the first principal of thermodynamics. Then, we obtain expressions for the entropy, the free energy, and the Gibbs potential. Searching for equilibrium states, we explore two possible systems: the canonical ensemble and the grand canonical ensemble. Studying the former, we conclude that there is no extrema for the free energy. Through the latter system, we obtain a minimum of the Gibbs potential when the macro-temperature and pressure of the cloud are equal to those of the surrounding medium. This minimum corresponds to a possible stable local equilibrium state of our system.https://www.mdpi.com/2218-1997/11/6/184molecular cloudsfluidsturbulenceself-gravitythermodynamics |
| spellingShingle | Sava Donkov Ivan Zh. Stefanov Valentin Kopchev Thermodynamics of Fluid Elements in the Context of Turbulent Isothermal Self-Gravitating Molecular Clouds Universe molecular clouds fluids turbulence self-gravity thermodynamics |
| title | Thermodynamics of Fluid Elements in the Context of Turbulent Isothermal Self-Gravitating Molecular Clouds |
| title_full | Thermodynamics of Fluid Elements in the Context of Turbulent Isothermal Self-Gravitating Molecular Clouds |
| title_fullStr | Thermodynamics of Fluid Elements in the Context of Turbulent Isothermal Self-Gravitating Molecular Clouds |
| title_full_unstemmed | Thermodynamics of Fluid Elements in the Context of Turbulent Isothermal Self-Gravitating Molecular Clouds |
| title_short | Thermodynamics of Fluid Elements in the Context of Turbulent Isothermal Self-Gravitating Molecular Clouds |
| title_sort | thermodynamics of fluid elements in the context of turbulent isothermal self gravitating molecular clouds |
| topic | molecular clouds fluids turbulence self-gravity thermodynamics |
| url | https://www.mdpi.com/2218-1997/11/6/184 |
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