ESDU Aero W.02.04.11 plots curves of h/b against Reynolds number for various values of l/b. Here h is the height of the crest of the wave above the undistorted profile surface, b is the wavelength and Reynolds number relates to the velocity outside the boundary layer at the position of the wave crest and is based on l, the length of the laminar layer on the undistorted surface. The data apply downstream of the first ten per cent of chord, and if several waves are present each should be treated separately.