Mechanism of Thicker Oil Film Formation Caused by Micro-Dimples Elucidated by Direct Observation with Laser-Induced Fluorescence

Micro-dimple is one of the promising surface texturing technologies to reduce friction loss due to the generation of thicker oil film caused by the cavitation occurrence around the micro-dimples. In this study, the flow behavior of oil film around micro-dimples was directly observed by laser-induced fluorescence (LIF). LIF observation for the oil flow showed that micro- dimples induced the cavitation occurrence that contributed to increase the oil film thickness. This was in good agreement with the results of the friction test, and it was thus proved that the cavitation occurrence by micro-dimples is significantly effective for the friction reduction.