Hybrid oil film approach to measuring skin friction distribution

This paper describes a technique for quantitatively measuring the time-averaged skin friction distribution on a wind tunnel test model. The technique is a hybrid oil film approach that is based on the combination of the qualitative skin friction distribution obtained from luminescent oil film and the quantitative local skin friction measurements obtained from oil film interferometry in another blowing of the same flow condition. To demonstrate its validity, the proposed method was applied to the flow field around a vortex generator on a flat plate, and successfully measured the quantitative skin friction distribution.