Dynamic and Static Properties of Recessed Hydrostatic Journal Bearings by Small Displacement Analysis

Coefficients are presented for hydrostatic stiffness, hydrodynamic stiffness and squeeze damping for capillary, orifice and constant flow control. Due to the linear behaviour of such bearings these coefficients may be used for conservative design and with reasonable accuracy where the displacements are less than half the clearance. The dynamic coefficients may also be employed to predict the onset of whirl. The results are illustrated by application to rotating and non-rotating load situations. It is demonstrated that the squeeze damping constant for the concentric condition may be obtained from a steady loading test for hydrodynamic stiffness since C_sq = λ_hd/(πN). It is argued that this relationship may be generalised for all types of bearings capable of exhibiting half-speed whirl operating at any speed.