LINEAR-STABILITY ANALYSIS OF FINITE POROUS JOURNAL BEARINGS - USE OF THE BRINKMAN-EXTENDED DARCY MODEL

On the basis of the Brinkman-extended Darcy model (BEDM), this paper examines the effects of viscous shear stresses on the linear stability of finite porous journal bearings. The result shows that the influences of viscous shear stresses on the dynamic performance of porous journal-bearing systems are apparent and not negligible. In certain regions of parameter space the BEDM predicts quite different stability characteristics to those derived using either the slip-flow model (SFM) or Darcy model (DM). In particular, a higher threshold speed (increased stability) is predicted using the BEDM for porous bearings with (i) small length-to-diameter ratios (lambda < 1) or (ii) low permeability parameters and high steady-state eccentricity ratios.