Experimental Measurement of Particle Dispersion in Turbulent Flow

The dispersion of particles in turbulent flows, phenomena such as dispersion, diffusion, and sedimentation, and a more fundamental point of view, the description of particle interaction with the turbulent field are recently of increasing interest. A system capable of investigating statistical structure of the motion of particles in a turbulent fluid flow using a turbulent water pipe flow system and particles tagged with C0-60 radioactive pellets has been constructed and tested. The particles were followed in their trajectory by a group of detectors consisting of NaI(Tℓ) crystals mounted on photomultiplier tubes which move with the particles on a movable carriage. From the photomultiplier voltages a time series of particle position and velocity was calculated. Results included Eulerian and convected frame measurements in the underlying fluid field in the pipe, representative measurements from recent experiments with particles, and an analysis of noise and statistical reliability of the results