ORGANIZED NATURE OF A TURBULENT TRAILING VORTEX

Experiments have been carried out into the turbulence structure of a low-Reynolds-number (15 x 10(3) < Re-GAMMA < 25 x 10(3), based on the maximum azimuthal velocity and core diameter) trailing vortex produced at the juncture of a flow aligned cylinder and a pair of oppositely loaded airfoils. Five different types of screens are placed ahead of the vortex generator. Components of the mean velocity, Reynolds stress flux, and quasiperiodic large-scale wavelengths have been measured. The turbulence structure varies with Rossby number. The vortex core is not a benign solid body of rotation. It has intermittent patches of turbulent and laminarescent fluid. The shear-stress-rich low-momentum core fluid intermittently ejects outwards in the direction of vortex rotation.