NACA Technical Reports

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 and optical viewing. From a correlation of results obtained from various sources at lower Mach numbers (in the range 2.0 to 4.5) and data from the present tests with variable Reynolds number per inch, 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