Study of Rotating Flow Driven by Corotating Disks in an Enclosure Using Particle Detection Across Radial Measurement Lines

We investigated the motion of small particles in a rotating flow driven by corotating disks within an enclosure featuring a partial shroud opening, experimenting flow in a hard disk drive (HDD). In HDDs, levitating particles from mechanical components can damage the disk or magnetic head. Using a refractive index-matched system for clear visualization, we tracked nearly neutrally buoyant particles and analyzed their trajectories in polar coordinates parallel to the disks. Particles initially moved outward due to centrifugal forces, collided with the shroud, and reflected inward at specific angles. Statistical analysis revealed preferred trajectories, with higher passage frequencies at certain positions, highlighting characteristic flow patterns.