Special Relativistic Hydrodynamics with CRONOS

TL;DR

This paper presents the extension of the CRONOS code to special relativistic hydrodynamics, emphasizing its adaptability, robustness, and validation across various coordinate systems and problems.

Contribution

The paper introduces a flexible, stable, and validated special relativistic hydrodynamics code based on CRONOS, supporting multiple coordinate systems and customizable numerical methods.

Findings

Successfully extended CRONOS to special relativity

Demonstrated robustness through extensive validation

Supports multiple coordinate systems and customizable modules

Abstract

We describe the special relativistic extension of the CRONOS code, which has been used for studies of gamma-ray binaries in recent years. The code was designed to be easily adaptable, allowing the user to easily change existing functionalities or introduce new modules tailored to the problem at hand. Numerically, the equations are treated using a finite-volume Godunov scheme on rectangular grids, which currently support Cartesian, spherical, and cylindrical coordinates. The employed reconstruction technique, the approximate Riemann solver and the equation of state can be chosen dynamically by the user. Further, the code was designed with stability and robustness in mind, detecting and mitigating possible failures early on. We demonstrate the code's capabilities on an extensive set of validation problems.