Abstract
We report on an attempt to realize direct visualization of the secondary flow in the planes parallel to the disks in a rotating flow driven by corotating disks mounted in a non-axisymmetric enclosure. The flow is based on the geometry of a hard disk drive used as information storage device. We developed a flow visualization system based on refractive index matching and Sheimpflug principle. The former allows undisturbed transparent view of whole the flow field without reflection and diffraction, while the latter provides sharply focused images at a tilted observation angle. The combination of these two techniques realized a direct visualization of the flow in the vertical planes for the first time. They allows in investigation of the secondary flow. We examined the secondary flow observed on two measurement planes vertical to the disk surfaces in the flow. The resulting behavior was consistent to the one reported in the past studies by other researchers. Further improvement of the image quality is required toward quantitative analysis of the flow.
