Abstract
The purpose of this paper is to present a thorough study on coupled vibration of multiple co-rotating disks stacked on a hub, which are the basic configuration of computer hard disk drives (HDD). The paper has two specific goals. The first goal is to demonstrate experimentally that presence of air will lead to exactly N distinct natural frequencies for each propagating wave with two or more nodal diameters, where N is the number of disks. The second goal is to illustrate experimentally and numerically that flexibility of spacers between the corotating disks can also lead to coupled disk vibration in the same manner.
