  We present measurements of fluid particle accelerations in turbulent water
flows between counter-rotating disks using three-dimensional Lagrangian
particle tracking. By simultaneously following multiple particles with
sub-Kolmogorov-time-scale temporal resolution, we measured the spatial
correlation of fluid particle acceleration at Taylor microscale Reynolds
numbers between 200 and 690. We also obtained indirect, non-intrusive
measurements of the Eulerian pressure structure functions by integrating the
acceleration correlations. Our experimental data provide strong support to the
theoretical predictions of the acceleration correlations and the pressure
structure function in isotropic high Reynolds number turbulence by Obukhov and
Yaglom in 1951. The measured pressure structure functions display K41 scaling
in the inertial range.
