Behavior of Spiral Flow Structures Along the Trailing Edges of E-Block Arms Under Increasing Airflow Velocities

The behavior of spiral flow structures along the trailing edges of the E-block arm has been investigated under increasing airflow velocities. These coherent structures in the flow are commonly believed to be closely associated with the flow induced vibrations on the E-block arms. The experiments showed that vortex shedding is detected in a hard disk drive (HDD) model when the motor speed is as low as 1200 rpm. A turbulent wake is formed immediately after flow over the E-block arms. Flow turbulence in the wake becomes significant from 7200 rpm onwards and peaked at 10 000 rpm. From 12 000 rpm onwards, a turbulent jet is formed instead of a turbulent wake. The flow regime change deserved further in-depth investigations in order to understand the flow physics so that future designs of HDD that run at even higher rotational speeds with acceptable track misregistration could be realizable