  We investigate the statistics of phase fluctuations of an acoustic wave
propagating through a turbulent flow in line of sight (LOS) configuration.
Experiments are performed on a closed von Karman swirling flow whose boundaries
are maintained at a constant temperature. In particular, we analyze the root
mean square (RMS) and the power spectrum density (PSD) of phase fluctuations. A
model is developed and analytical predictions obtained for these quantities
using geometrical acoustics are shown to be in agreement with experimental
observations.
