Hydrodynamical adaptive mesh refinement simulations of turbulent flows - I. Substructure in a wind

TL;DR

This paper introduces optimized adaptive mesh refinement criteria for hydrodynamical simulations, improving the resolution of turbulence and flow structures behind a moving subcluster during mergers.

Contribution

It presents novel AMR criteria tailored to better capture turbulence in 3D hydrodynamical simulations of merging subclusters.

Findings

Enhanced resolution of turbulent wake and shear instabilities.

Better modeling of subcluster core morphology evolution.

Implications for understanding cluster cold fronts.

Abstract

The problem of the resolution of turbulent flows in adaptive mesh refinement (AMR) simulations is investigated by means of 3D hydrodynamical simulations in an idealised setup, representing a moving subcluster during a merger event. AMR simulations performed with the usual refinement criteria based on local gradients of selected variables do not properly resolve the production of turbulence downstream of the cluster. Therefore we apply novel AMR criteria which are optimised to follow the evolution of a turbulent flow. We demonstrate that these criteria provide a better resolution of the flow past the subcluster, allowing us to follow the onset of the shear instability, the evolution of the turbulent wake and the subsequent back-reaction on the subcluster core morphology. We discuss some implications for the modelling of cluster cold fronts.