Impact of bulk viscosity on flow morphology of shock-accelerated cylindrical light bubble in diatomic and polyatomic gases

2021 ◽  
Vol 33 (6) ◽  
pp. 066103
Author(s):  
Satyvir Singh ◽  
Marco Battiato ◽  
R. S. Myong
Keyword(s):  
Bulk Viscosity ◽  
Polyatomic Gases ◽  
Flow Morphology

Shock Front Thickness and Bulk Viscosity in Polyatomic Gases

1956 ◽  
Vol 24 (4) ◽  
pp. 767-770 ◽  
Author(s):  
W. H. Andersen ◽  
D. F. Hornig
Keyword(s):  
Shock Front ◽  
Bulk Viscosity ◽  
Polyatomic Gases

scholarly journals Relativistic Rational Extended Thermodynamics of Polyatomic Gases with a New Hierarchy of Moments

Entropy ◽  
2021 ◽  
Vol 24 (1) ◽  
pp. 43
Author(s):  
Takashi Arima ◽  
Maria Cristina Carrisi ◽  
Sebastiano Pennisi ◽  
Tommaso Ruggeri
Keyword(s):  
Bulk Viscosity ◽  
Maximum Entropy Principle ◽  
Entropy Density ◽  
Extended Thermodynamics ◽  
Bgk Model ◽  
Rest Energy ◽  
Polyatomic Gases ◽  
The Cauchy Problem ◽  
Entropy Principle ◽  
Rational Extended Thermodynamics

A relativistic version of the rational extended thermodynamics of polyatomic gases based on a new hierarchy of moments that takes into account the total energy composed by the rest energy and the energy of the molecular internal mode is proposed. The moment equations associated with the Boltzmann–Chernikov equation are derived, and the system for the first 15 equations is closed by the procedure of the maximum entropy principle and by using an appropriate BGK model for the collisional term. The entropy principle with a convex entropy density is proved in a neighborhood of equilibrium state, and, as a consequence, the system is symmetric hyperbolic and the Cauchy problem is well-posed. The ultra-relativistic and classical limits are also studied. The theories with 14 and 6 moments are deduced as principal subsystems. Particularly interesting is the subsystem with 6 fields in which the dissipation is only due to the dynamical pressure. This simplified model can be very useful when bulk viscosity is dominant and might be important in cosmological problems. Using the Maxwellian iteration, we obtain the parabolic limit, and the heat conductivity, shear viscosity, and bulk viscosity are deduced and plotted.

scholarly journals Rational extended thermodynamics of dense polyatomic gases incorporating molecular rotation and vibration

2020 ◽  
Vol 378 (2170) ◽  
pp. 20190176 ◽  
Author(s):  
Takashi Arima ◽  
Tommaso Ruggeri ◽  
Masaru Sugiyama
Keyword(s):  
Bulk Viscosity ◽  
Rarefied Gas ◽  
Molecular Rotation ◽  
Extended Thermodynamics ◽  
Molecular Vibration ◽  
Duality Principle ◽  
Linear Wave ◽  
Polyatomic Gases ◽  
Dense Gases ◽  
Rational Extended Thermodynamics

The paper aims to construct a rational extended thermodynamics (RET) theory of dense polyatomic gases by taking into account the experimental evidence that the relaxation time of molecular rotation and that of molecular vibration are quite different from each other. For simplicity, we focus on gases with only one dissipative process due to bulk viscosity. In fact, in some polyatomic gases, the effect of bulk viscosity is much larger than that of shear viscosity and heat conductivity. The present theory includes the previous RET theory of dense gases with six fields as a particular case, and it also includes the RET theory of rarefied polyatomic gases with seven fields in the rarefied-gas limit. The closure is carried out by using the universal principles, that is, Galilean invariance and objectivity, entropy principle, and thermodynamic stability (convexity of entropy), where the duality principle connecting rarefied gases to dense gases also plays an important role. A detailed discussion is devoted to the expression of the production terms in the system of balance equations. As typical examples, we study a gas with virial equations of state and a van der Waals gas. Lastly the dispersion relation of a linear wave is derived, and its comparison with experimental data is made. This article is part of the theme issue ‘Fundamental aspects of nonequilibrium thermodynamics’.

SHORT-TERM EVOLUTION OF FLOW & MORPHOLOGY IN AN ERODIBLE MEANDERING CHANNEL WITH & WITHOUT GROYNES

2018 ◽  
Vol 74 (4) ◽  
pp. I_1147-I_1152
Author(s):  
Saroj KARKI ◽  
Yuji HASEGAWA ◽  
Masakazu HASHIMOTO ◽  
Hajime NAKAGAWA ◽  
Kenji KAWAIKE
Keyword(s):  
Short Term ◽  
Meandering Channel ◽  
Term Evolution ◽  
Flow Morphology
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