Research and Validation of Global Skin Friction Measurement Techniques Based on Fluorescent Oil Film

摘要

The Skin friction, along with skin pressure and temperature, is one of the most important skin factors in aerodynamics and fluid dynamics, meanwhile, but also the most difficult measurement skin factor. Compared with single point and indirect characters of traditional ways, global skin friction direct measurement method based on fluorescent oil film was developed. By investigation and research, the governing equation of fluorescent oil film, which expresses the relationship between the oil film thickness and skin friction, was established. Furthermore, this equation was solved by introducing additional constraint and using integral minimization approach and variation approach which was similar to the solution of Optical Flow proposed by Horn et al. Then a specific fluorescent indicator excited by ultraviolet light was chosen to develop the fluorescent oil film and a 2K.x2K resolution CCD camera was used to record the oil film image. At last, delta wing skin friction measurement experiment was carried out, and high resolution skin friction distribution was acquired and consistent with the theoretical analysis.