Random Surface Roughness Effects in Microasperity Lubrication

It is well known that the classical theory of lubrication does not predict the existence of a stable hydrodynamic film between two parallel surfaces. Experimental results have shown that the surface roughness (asperities and cavities) helps the pressure buildup between the two surfaces, thus maintaining the load support that keeps the surfaces from collapsing into each other. The effect of surface roughness on lubrication has gained considerable attention since it is widely recognized that surface roughness can alter the solution for pressure and leakage in hydrodynamic bearings from that given by classical theory. The present work investigates the effect of random (stochastic) surface roughness on the lubrication characteristics of a thrust ring engineered with deterministic surface features.