Study on Flow Induced Vibration of Head Disk Assembly Mechanisms with High Speed Rotating Disks (1st Report, Experimental Analysis by Measuring the Air Flow Velocity in the Head Disk Assembly Mechanisms)

The authors have studied the relationship between the disk flutter vibration and the ambient pressure in the test disk enclosure, as a function of disk rotational velocity. It was found that the disk flutter amplitude decreases by reducing the ambient pressure in the test disk enclosure. In addition, the authors have also measured flow induced flutter vibration of co-rotating two disks by using LDV as well as air flow velocity between two disks by using the hot-wire anemometer. From the experimental results, it was found that the arm which is inserted between two disks suppresses the disk flutter vibration. The arm shape and thickness, however, do not affect the disk flutter vibration virtually. The mean flow velocity as well as its fluctuation decrease, when the arm is inserted between two disks. Therefore, it is suggested that disk flutter can be suppressed by inserting the arm or spoiler that decreases flow fluctuation between two disks.