VETTAM

• Verfasst von: Menon, Shyam H. [VerfasserIn]
• Verfasst von: Federrath, Christoph [VerfasserIn]
• Verfasst von: Krumholz, Mark R. [VerfasserIn]
• Verfasst von: Kuiper, Rolf [VerfasserIn]
• Verfasst von: Wibking, Benjamin D [VerfasserIn]
• Verfasst von: Jung, Manuel [VerfasserIn]
• Titel: VETTAM
• Titelzusatz: a scheme for radiation hydrodynamics with adaptive mesh refinement using the variable Eddington tensor method
• Verf.angabe: Shyam H Menon, Christoph Federrath, Mark R Krumholz, Rolf Kuiper, Benjamin D Wibking, Manuel Jung
• E-Jahr: 2022
• Jahr: 22 February 2022
• Umfang: 23 S.
• Fussnoten: Gesehen am 12.04.2022
• Titel Quelle: Enthalten in: Royal Astronomical SocietyMonthly notices of the Royal Astronomical Society
• Ort Quelle: Oxford : Oxford Univ. Press, 1827
• Jahr Quelle: 2022
• Band/Heft Quelle: 512(2022), 1, Seite 401-423
• ISSN Quelle: 1365-2966
• DOI: doi:10.1093/mnras/stac485
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1799290182

Abstract

We present Variable Eddington Tensor (VET)-closed Transport on Adaptive Meshes (VETTAM), a new algorithm to solve the equations of radiation hydrodynamics (RHD) with support for adaptive mesh refinement (AMR) in a frequency-integrated, two-moment formulation. The method is based on a non-local VET closure computed with a hybrid characteristics scheme for ray tracing. We use a Godunov method for the hyperbolic transport of radiation with an implicit backwards-Euler temporal update to avoid the explicit time-step constraint imposed by the light-crossing time, and a fixed-point Picard iteration scheme to handle the nonlinear gas-radiation exchange term, with the two implicit update stages jointly iterated to convergence. We also develop a modified wave-speed correction method for AMR, which we find to be crucial for obtaining accurate results in the diffusion regime. We demonstrate the robustness of our scheme with a suite of pure radiation and RHD tests, and show that it successfully captures the streaming, static diffusion, and dynamic diffusion regimes and the spatial transitions between them, casts sharp shadows, and yields accurate results for rates of momentum and energy exchange between radiation and gas. A comparison between different closures for the radiation moment equations, with the Eddington approximation (0th-moment closure) and the M1 approximation (1st-moment closure), demonstrates the advantages of the VET method (2nd-moment closure) over the simpler closure schemes. VETTAM has been coupled to the AMR FLASH (magneto-)hydrodynamics code and we summarize by reporting performance features and bottlenecks of our implementation.