SPACE-TIME VELOCITY CORRELATIONS IN THE IMPELLER STREAM OF A RUSHTON TURBINE

Simultaneous velocity measurements at two points have been carried out with a two-component laser Doppler velocimeter in order to characteri se the turbulence along the impeller stream of a Rushton turbine in a water tank. In addition to mean values of the velocity and its fluctua tions, space-time correlations have been studied to enable the determi nation of the convection velocity as well as of the scales of the turb ulent structures and to investigate the validity of Taylor's hypothesi s. A correction to the relationship between space and time correlation s is proposed.