Measurements of Mean Flow Velocity Beyond a Rotating Disk

Measurements were made of the mean velocity components of the turbulent flow field just beyond the edge of a thin disk rotating in its own plane. An approximate analysis was made of the turbulent strongly swirling radial jet flow region by recourse to the momentum integral technique. Comparison with experiment indicated that approximate similarity of both the tangential and radial velocity components was achieved in a few disk thicknesses. The angle of the flow from radial in the disk plane compared fairly well with that predicted by the present analysis but poorly with the exact asymptotic theory. Nearly discrete frequency vortex shedding at the disk edge was detected by pressure-correlation measurements just outside the boundary layer.