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This study explores Relativistic Smoothed Particle Hydrodynamics (RSPH) for gas dynamics in astrophysical environments, emphasizing energy-momentum and baryon number conservation and entropy-based calculations. Developed to analyze systems without grids, this Lagrangian method is applicable in 1, 2, and 3 dimensions, offering insights into shocks, artificial viscosity, and thermodynamics. Drawing on seminal works, this research details the RSPH equations for studying ultrarelativistic pion gases, shock waves, and thermodynamically normal and anomalous matter. Utilizing techniques like Monte Carlo sampling and Lagrangian formulations, it presents numerical solutions for various scenarios in astrophysical settings.
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Relativistic Smoothed Particle Hydrodynamics C.E. Aguiar, T. Kodama U.F. Rio de Janeiro T. Osada,Y. Hama U. São Paulo • Outline • Relativistic hydrodynamics • Relativistic SPH • Entropy-based SPH • Shocks and artificial viscosity
Relativistic Hydrodynamics Energy-momentum conservation Baryon-number conservation
Baryon number conservation: comoving derivative:
enthalpy per baryon: Energy-momentum conservation:
Momentum equation: Energy equation:
Entropy conservation: s = entropy density (rest frame)
SPH • Developed to study gas dynamics in astrophysical systems. • Lagrangian method. • No grids. • Arbitrary geometries. • Equally applicable in 1, 2 and 3 space • dimensions. - L.Lucy, Astron.J. 82, 1013 (1977) - R.Gingold, J.Monaghan, MNRAS 181, 378 (1977) Reviews: - J. Monaghan, Annu. Rev. Astron. Astrophys. 30, 543 (1992) - L. Hernquist, N. Katz, Ap. J. Suppl. 70, 419 (1989)
Smoothing h x 0 Error:
Particles "Monte-Carlo" sampling nb = baryon number of ''particle'' b
Different ways of writing SP estimates (we omit the SP subscript from now on):
Derivatives No need for finite differences and grids: D D i+1 i-1 i
Momentum equation Energy equation
? Particle Velocity equation for g:
Pion Gas Rarefaction Wave
Pion Gas Landau Solution
numerical calculation shock wave x Shock Waves
Pion Gas Shock Wave
Second Law of Thermodynamics: Thermodynamically normal matter: Thermodynamically anomalous matter:
Pion Gas Shock Wave
Pion Gas Rankine - Hugoniot:
QGP + Pions Rarefaction Shock
QGP + Pions Rarefaction Shock
QGP + Pions Rarefaction Shock