A Numerical Scheme for Static and Dynamic Simulation of Subambient Pressure Shaped Rail Sliders

Abstract

A numerical scheme based on the finite difference technique is developed to simulate the steady-state flying conditions and dynamic responses of subambient pressure sliders with shaped rails. In order to suppress numerical difficulties caused by the clearance discontinuities present in the subambient pressure sliders, the control volume formulation of the linearized generalized lubrication equation is utilized. For the shaped rail sliders, a method of averaging the mass flow across the rail boundaries is implemented. Furthermore, the power-law scheme by Patankar, is implemented in calculating the mass flows. The resulting equation is solved using the alternating direction implicit method. For the simulation of steady-state flying conditions, a variable time step algorithm is implemented for the purpose of reaching the steady-state values as quickly as possible. This numerical scheme is very efficient in that the coarse finite difference mesh is sufficient for numerical stability, and that the time step changer very much improves the convergence rate. The static flying heights of the Transverse Pressure Contour and the “Guppy” slider are calculated for different disk velocities and slider skew angles. For the Guppy slider, the dynamic responses of the slider to a cosine bump and disk runout are simulated.