Effects of mass transfer on transition behavior at high speeds

Surface heat transfer and boundary layer transition measurements have been performed on a slender blunted cone at M sub infinity = 8.0. These measurements have been obtained on the conical surface with mass transfer occurring on the spherical nose cap. The free stream Reynolds number, based on nose radius, varied between 6000 and 90000. Data were obtained both at zero angle of attack and at angles as high as 14 degrees, which exceeds the semivertex cone angle of 10 degrees. The technique utilized in the determination of transition location was the observation of the RMS output of a thin film gauge, imbedded in the model surface, and maintained at a constant temperature by an anemometer system. A sudden change in the RMS output of the film gauge was found to accurately locate the onset of boundary layer transition.