  Studies of surface brightness fluctuations in the intracluster medium (ICM)
present an indirect probe of turbulent properties such as the turbulent
velocities, injection scales, and the slope of the power spectrum of
fluctuations towards smaller scales. With the advancement of Sunyaev-Zel'dovich
(SZ) studies and surveys relative to X-ray observations, we seek to investigate
surface brightness fluctuations in a sample of SPT-SZ clusters which also have
archival \textit{XMM-Newton} data. Here we present a pilot study of two typical
clusters in that sample: SPT-CLJ0232-4421 and SPT-CLJ0638-5358. We infer
injection scales larger than 500 kpc in both clusters and Mach numbers $\approx
0.5$ in SPT-CLJ0232-4421 and Mach numbers $\approx 0.6 - 1.6$ in
SPT-CLJ0638-5358, which has a known shock. We find hydrostatic bias values for
$M_{500}$ less than 0.2 for SPT-CLJ0232-4421 and less than 0.1 for
SPT-CLJ0638-5358. These results show the importance to assess its quantitative
values via a detailed multiwavelength approach and suggest that the drivers of
turbulence may occur at quite larger scales.
