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Title: SIMPLE WAVES IN IDEAL RADIATION HYDRODYNAMICS

Abstract

In the dynamic diffusion limit of radiation hydrodynamics, advection dominates diffusion; the latter primarily affects small scales and has negligible impact on the large-scale flow. The radiation can thus be accurately regarded as an ideal fluid, i.e., radiative diffusion can be neglected along with other forms of dissipation. This viewpoint is applied here to an analysis of simple waves in an ideal radiating fluid. It is shown that much of the hydrodynamic analysis carries over by simply replacing the material sound speed, pressure, and adiabatic index with the values appropriate for a radiating fluid. A complete analysis is performed for a centered rarefaction wave, and expressions are provided for the Riemann invariants and characteristic curves of the one-dimensional system of equations. The analytical solution is checked for consistency against a finite difference numerical integration, and the validity of neglecting the diffusion operator is demonstrated. An interesting physical result is that for a material component with a large number of internal degrees of freedom and an internal energy greater than that of the radiation, the sound speed increases as the fluid is rarefied. These solutions are an excellent test for radiation hydrodynamic codes operating in the dynamic diffusion regime. The generalmore » approach may be useful in the development of Godunov numerical schemes for radiation hydrodynamics.« less

Authors:
 [1]
  1. Lawrence Livermore National Laboratory, L-023, 7000 East Avenue, Livermore, CA 94550-9698 (United States)
Publication Date:
OSTI Identifier:
21279424
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 693; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/693/2/1637; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ADVECTION; ANALYTICAL SOLUTION; DEGREES OF FREEDOM; DIFFUSION; EQUATIONS; HYDRODYNAMICS; IDEAL FLOW; ONE-DIMENSIONAL CALCULATIONS; RADIANT HEAT TRANSFER; SOUND WAVES; VELOCITY

Citation Formats

Johnson, Bryan M. SIMPLE WAVES IN IDEAL RADIATION HYDRODYNAMICS. United States: N. p., 2009. Web. doi:10.1088/0004-637X/693/2/1637; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
Johnson, Bryan M. SIMPLE WAVES IN IDEAL RADIATION HYDRODYNAMICS. United States. https://doi.org/10.1088/0004-637X/693/2/1637; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)
Johnson, Bryan M. 2009. "SIMPLE WAVES IN IDEAL RADIATION HYDRODYNAMICS". United States. https://doi.org/10.1088/0004-637X/693/2/1637; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
@article{osti_21279424,
title = {SIMPLE WAVES IN IDEAL RADIATION HYDRODYNAMICS},
author = {Johnson, Bryan M},
abstractNote = {In the dynamic diffusion limit of radiation hydrodynamics, advection dominates diffusion; the latter primarily affects small scales and has negligible impact on the large-scale flow. The radiation can thus be accurately regarded as an ideal fluid, i.e., radiative diffusion can be neglected along with other forms of dissipation. This viewpoint is applied here to an analysis of simple waves in an ideal radiating fluid. It is shown that much of the hydrodynamic analysis carries over by simply replacing the material sound speed, pressure, and adiabatic index with the values appropriate for a radiating fluid. A complete analysis is performed for a centered rarefaction wave, and expressions are provided for the Riemann invariants and characteristic curves of the one-dimensional system of equations. The analytical solution is checked for consistency against a finite difference numerical integration, and the validity of neglecting the diffusion operator is demonstrated. An interesting physical result is that for a material component with a large number of internal degrees of freedom and an internal energy greater than that of the radiation, the sound speed increases as the fluid is rarefied. These solutions are an excellent test for radiation hydrodynamic codes operating in the dynamic diffusion regime. The general approach may be useful in the development of Godunov numerical schemes for radiation hydrodynamics.},
doi = {10.1088/0004-637X/693/2/1637; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)},
url = {https://www.osti.gov/biblio/21279424}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 693,
place = {United States},
year = {Tue Mar 10 00:00:00 EDT 2009},
month = {Tue Mar 10 00:00:00 EDT 2009}
}