Hydrodynamical adaptive mesh refinement simulations of turbulent flows - II. Cosmological simulations of galaxy clusters

TL;DR

This paper uses adaptive mesh refinement simulations to study turbulence in galaxy clusters, revealing that different AMR strategies improve resolution and show turbulence is widespread with significant velocity and pressure effects.

Contribution

It compares two AMR refinement criteria in cosmological simulations, demonstrating their effectiveness in resolving turbulence in galaxy clusters.

Findings

Turbulent velocity exceeds 200 km/s in cluster cores

Turbulence covers large areas, not just volume

Refined AMR criteria increase turbulent pressure contribution

Abstract

The development of turbulent gas flows in the intra-cluster medium and in the core of a galaxy cluster is studied by means of adaptive mesh refinement (AMR) cosmological simulations. A series of six runs was performed, employing identical simulation parameters but different criteria for triggering the mesh refinement. In particular, two different AMR strategies were followed, based on the regional variability of control variables of the flow and on the overdensity of subclumps, respectively. We show that both approaches, albeit with different results, are useful to get an improved resolution of the turbulent flow in the ICM. The vorticity is used as a diagnostic for turbulence, showing that the turbulent flow is not highly volume-filling but has a large area-covering factor, in agreement with previous theoretical expectations. The measured turbulent velocity in the cluster core is larger than 200 km/s, and the level of turbulent pressure contribution to the cluster hydrostatic equilibrium is increased by using the improved AMR criteria.