Lagrangian acceleration measurements at large Reynolds numbers

We report experimental measurements of Lagrangian accelerations in a turbulent water flow between counter-rotating disks for Taylor-Reynolds numbers 900 < R-lambda < 2000. Particle tracks were recorded by imaging tracer particles onto a position sensitive photodiode, and Lagrangian information was obtained from fits to the position versus lime data. Several challenges associated with extracting Lagrangian statistical quantities from particle tracks are addressed. The acceleration variance is obtained as a function of Reynolds number and shows good agreement with Kolmogorov (1941) scaling. The Kolmogorov constant for the acceleration variance is found to be a(0) = 7 +/- 3. (C) 1998 American institute of Physics.