Turbulence in the intracluster medium: simulations, observables &
  thermodynamics
  We conduct two kinds of homogeneous isotropic turbulence simulations relevant
for the intracluster medium (ICM): (i) pure turbulence runs without radiative
cooling; (ii) turbulent heating$+$radiative cooling runs with global thermal
balance. For pure turbulence runs in the subsonic regime, the rms density and
surface brightness (SB) fluctuations vary as the square of the rms Mach number
($\mathcal{M}_{\text{rms}}$). However, with thermal balance, the density and SB
fluctuations $(\delta SB/SB)$ are much larger. These scalings have implications
for translating SB fluctuations into a turbulent velocity, particularly for
cool cores. For thermal balance runs with large (cluster core) scale driving,
both the hot and cold phases of the gas are supersonic. For small scale (one
order of magnitude smaller than the cluster core) driving, multiphase gas forms
on a much longer timescale but $\mathcal{M}_{\text{rms}}$ is smaller. Both
small and large scale driving runs have velocities larger than the Hitomi
results from the Perseus cluster. Thus turbulent heating as the dominant
heating source in cool cluster cores is ruled out if multiphase gas is assumed
to condense out from the ICM. Next we perform thermal balance runs in which we
partition the input energy into thermal and turbulent parts and tune their
relative magnitudes. The contribution of turbulent heating has to be $\lesssim
10\%$ in order for turbulence velocities to match Hitomi observations. If the
dominant source of multiphase gas is not cooling from the ICM (but say uplift
from the central galaxy), the importance of turbulent heating cannot be
excluded.
