Observation and numerical simulation of oil-film formation under reciprocating rolling point contact

A basic study on oil-film formation in reciprocating pure rolling point contact was conducted by optical interferometry observation and numerical analysis. In the analysis the program code published by Venner and Lubrecht was extended for time dependent and starved problems. The observations showed that the oil-film thickness in reciprocating rolling was less than that in unidirectional rolling; this because of the starved condition that was induced by cavitation generated in the previous passing of the contacting region and which survived in the inlet region for a while after reversal. The Elrod algorithm was used in the numerical analysis, and the amount of oil on the trailing edge of the calculation domain was stored and used on the leading edge of the calculation domain when it returned after reversal. In this calculation model, the oil-film thickness decreased with cycle repetition, while in the fully flooded condition the oil-film almost recovered when the contacting area returned to the stroke center, and nearly the same oil-film thickness trajectory was traced along with changes of the entrainment velocity.