Investigation of Polygonal Airflow Structure in Hard Disk Drives With and Without Spoiler by Using Fluid Simulations and Measurements

The polygonal airflow patterns between disks in hard disk drives (HDDs) were investigated by using fluid simulations and pressure measurements. These patterns were found from the radial velocity distributions of airflows on the mid-plane between disks. Several peaks of pressure increases caused by rotating polygonal-airflow patterns with several modes were measured with a pressure sensor placed on the tip of the carriage arm and spoiler. Several modes of polygonal patterns were observed at the outer diameter (OD) and the middle diameter (MD) arm positions, but not at the inner diameter (ID) arm position. These peaks on the arm were weakened by the spoiler.