Exploratory investigation of boundary-layer transition on a hollow cylinder at a Mach number of 6.9

The Reynolds number for transition on the outside of a hollow cylinder with heat transfer from the boundary layer to the wall has been investigated at a Mach number of 6.9 in the Langley 11-inch hypersonic tunnel. The type of boundary layer was determined from impact-pressure surveys. When only the results obtained in the portion of the nozzle where surveys indicated the Mach number to be essentially constant were considered, the Reynolds number for the start of transition was between 4 x 10(exp 6) and 6 x 10(exp 6). From a correlation of results obtained from various sources at lower Mach numbers (in the range 2.0 to 4.5), leading-edge thickness and free-stream Reynolds number per inch appear to be important considerations in flat-plate transition results. At a given Mach number, it appears that the Reynolds number based on leading-edge thickness is an important parameter that must be considered in comparisons of flat-plate transition data from various installations.