The 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 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.