Measurements of Turbulent Friction on a Smooth Flat Plate in Supersonic Flow

Direct measurements of supersonic local skin friction, using the -element technique, are presented for Mach Numbers from 2.0 to 4.5 and Reynolds Numbers from 3 X 10^5 to 9 X 10^6. Turbulent and transition are emphasized, although some measurements the laminar regime are included. The observed effect compressibility is to reduce the magnitude of turbulent skin by a factor of two at a Mach Number of 4.5 and a number of about 10^7. boundary-layer momentum-integral equation for constant is verified within a few per cent by two experimental . Typical static pressure measurements are presented to that transition can be detected by observing disturbances pressure associated with changes in displacement thickness the boundary layer. is found that the turbulent boundary layer cannot be defined for values of u_1 θ/v_1 less than about 2,000, where θ is the momentum thickness. For larger values of u_1 θ/v_1, there is a relationship between local friction coefficient and momentum-thickness Reynolds Number at a fixed Mach Number. The compares the present measurements at M = 2.5 with data from other sources.