Lagrangian dispersion in turbulent flow from laser transit anemometry

The Lagrangian dispersion function in turbulent flow can be determined from measurements of the probability that a particle which is observed in a small volume is not observed in a similar size volume downstream. In this work a single‐detector method is proposed to detect the particle arrivals in a multiple series of scattering volumes; the probability can be determined from the digital record over a long time compared to the turbulent integral time scale. The method is tested at locations downstream of a water spray nozzle and a submerged jet of dilute polymer solutions.