Effect of turbulent integral scale on probability after-effect measurements

Abstract

The probability after-effect function determined from particle arrival statistics in two long thin scattering volumes is shown to depend upon the Lagrangian velocity correlation function in homogeneous isotropic turbulence. Experimental measurements at three locations in a submerged water jet result in cross-stream turbulent intensities in agreement with laser Doppler velocimetry measurements obtained previously. In addition, the probability after-effects method yields the Lagrangian integral timescale. The success of the techniques suggests a combination with the two-spot time of flight velocimeter to give two components of the turbulent velocity fluctuations.