Characterisation of rough-wall drag in compressible turbulent boundary layers
This study investigates the applicability of incompressible roughness parameters in compressible turbulent boundary layers across a wide range of Mach and Reynolds numbers, revealing that while velocity transformations have limited impact, the fully rough regime exhibits a Mach-number-dependent shift that is best addressed by a temperature-ratio-based correction factor, thereby highlighting the need for custom rough-wall transformations.