Flow-Induced Slider Vibration in a Functional Hard Disk Drive: Influence of Air Shroud

An air shroud is designed and placed within a commercially available hard disk drive operating at 15 000 rpm. Large eddy simulations of the turbulent airflow characteristics resulting from both the models, with and without air shroud, are carried out by assuming the read/write head is at the disk middle diameter. The numerical model consists of about nine million tetrahedral cells with the largest and smallest sizes of the cell volumes being 2.5 mm³ and 0.35 mm³ , respectively. The dynamic Smagorinsky-Lily model is employed to mimic the effect of small-scale eddies in the turbulent airflow. Numerically predicted airflow characteristics are compared against the LDA measurements and found to be in good agreement. The wind blowing on the surfaces of the head gimbals assembly is converted into aerodynamic forces and the resulting slider displacement in the off-track and out-of-plane directions are investigated. It is inferred that the disk drive model with air shroud results in a maximum of 44% and 10% less off-track and out-of-plane slider displacements, respectively.