Dense Lagrangian particle tracking in homogeneous turbulence

We present measurements of dense fields of fluid particle trajectories in homogeneous turbulence at Re lambda -270 and -350 in a von Karman flow between two counter-rotating propellers. Applying the Shake-The-Box particle tracking algorithm, we are able to instantaneously track up to 100.000 particles in a volume of 50x50x15mm3. The mean inter-particle distance is lower than 7 Kolmogorov lengths. An interpolation scheme (FlowFit) with inherent physical constraints is used to interpolate the scattered velocity and acceleration data onto a Cartesian grid, in order to recover the smallest flow scales. In the presentation, we show velocity and acceleration statistics, compute the energy dissipation rate directly and compare it to indirect approaches