Experimental studies of the boundary layer on a flat plate at mach numbers from 2.5 to 4.5

Abstract

This Report presents an experimental investigation of the turbulent boundary layer on a large, thermally-insulated flat plate, in which Mach-number and total-temperature profiles and shear stress at the wall were measured. The measured velocity profiles are found to be in fairly good agreement with a number of theoretical treatments. Similarly, the measured skin-friction coefficients are fairly well predicted by flat-plate skin-friction laws. The form of the total-temperature profile close to the wall suggests an increase in turbulent Prandtl number as the wall is approached. At all conditions, the wall temperature was found to be higher than would be expected in adiabatic-flow conditions, whilst there was a substantial deficit of enthalpy flux within the boundary layer. Subsequent tests suggested that this enthalpy deficit should be attributed to small errors in the temperature measured by this particular probe.