Turbulent flow in a swirling free jet

The flow between two equal diameter disks, one turning and the other stationary, was examined experimentally. Two aluminum disks 15 cm in diameter, one turning at fixed speeds, were exposed to an air jet while velocities were observed at different separation distances between the disks by hot wire and X-wire anemometry. Numerical models were developed to predict the velocity distributions in the interdisk region. The maximal radial and tangential speeds were found to decrease asymptotically with increasing distance from the axis of rotation. Accurate modeling was achieved for the mean velocities and turbulent stresses, while the tangential velocity was found to be asymmetric about nu equals O, implying that the Boussinesq assumption is invalid