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 e xamines the effects of viscous shear stresses on the linear stability of finite porous journal bearings. The result shows that the influence s of viscous shear stresses on the dynamic performance of porous journ al-bearing systems are apparent and not negligible. In certain regions of parameter space the BEDM predicts quite different stability charac teristics to those derived using either the slip-flow model (SFM) or D arcy model (DM). In particular, a higher threshold speed (increased st ability) is predicted using the BEDM for porous bearings with (i) smal l length-to-diameter ratios (lambda < 1) or (ii) low permeability para meters and high steady-state eccentricity ratios.