Measurements of oil film thickness according to the capacitive method as carried out on a disc machine with discs having a surface roughness of 10 μin c.l.a. showed marked deviations from the theoretical values predicted by Dowson and Higginson (1)†, especially in the region of small film thickness, i.e. smaller than 0–6 μm (23·6 [μin).
In this paper the authors show that surface roughness is the cause of this discrepancy.
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