On Selection of Flow Modes between Rotating Disks

We investigate flow between co-rotating disks with a narrow gap, enclosed by a stationary shroud at the circumference, using the flow visualization with aluminum flakes, PIV analysis and the measurement by a laser-Doppler velocimetry. Experiments are conducted methodically concerning three system parameters, that is, disk-tip Reynolds number, gap aspect ratio and dimensionless peripheral radius. As a result, time-averaged flow fields are characterized as roughly two-dimensional. Stability diagrams are specified in terms of the three governing parameters. The rotational speed of a central core configuration obviously depends upon flow modes, which approximately coincides with the Kirchhoff's potential theory, while the radius of the configuration does not. Furthermore, we propose a theoretical modeling for flow modes.