A modular method for skin friction estimation in compressible boundary layers

The fluid property variation caused by viscous heating implies that empirical skin friction formulas of the form c_f = fcn(Re_θ) are not directly applicable to supersonic boundary layers. We present a method based on the work of Huang et al. (AIAA Journal 1993 31:9, pp. 1600–1604) that estimates the friction and heat transfer coefficients from the Mach number, Reynolds number, and wall temperature. The method is modular in the sense that it works with multiple near-wall scaling formulas ("velocity transformations''), velocity-temperature relationships, and can be calibrated against any incompressible skin friction formula.