Abstract
The authors consider the flow between co-rotating disks, namely, the disks which rotate co-axially in the same direction at the same angular velocity, with a narrow gap enclosed by a stationary shroud at their circumferences. The flow often accompanies an azimuthally-fluctuating instability; a non-axisymmetric secondary flow near the shroud. In this study, the authors experimentally research outer vortex modes, namely changing disk-tip Reynolds numbers Re and gap aspect ratio δ. The authors use the experimental apparatus which has a pair of co-rotating disks in the stationary cylindrical enclosure. So the experimental apparatus is filled up the 64wt% Nal aq. including silica oxide particles with fluorescent paint and YAG laser lightened up on the meridian plane (r-z plane) between co-rotating disks. Then, the authors conduct the visualisations of r-z plane using high-speed video camera at each experimental parameter and carried out Particle Image Velocimetry (PIV) analyses.
