Abstract:
Skin friction contributes an important part of the total resistance of aircraft in flight, and the measurement of skin friction has very important significance and value for researches of turbulence, boundary layer, drag reduction and thermal protection, etc. A global skin friction direct measurement method based on fluorescent oil film was introduced. The governing equation of fluorescent oil film was established to definite the relationship between the oil film thickness and skin friction, and solved by the introduction of additional constraints and using integral minimization approach and variation approach. The fluorescent oil film excited by ultraviolet light was explored, the ultraviolet light source and a high resolution CCD camera were used to establish a set of hardware system. A specific delta wing skin friction measurement experiment was carried out, and high resolution skin friction distribution of relative amplitude was acquired and compared with the theoretical analysis, the effectiveness of global skin friction direct measurement method based on fluorescent oil film is validated.