Experimental Investigation Of The Pressure Rise Required For The Incipient Separation Of Turbulent Boundary Layers In Two Dimensional Supersonic Flow PDF Download

The report describes the results of a wind-tunnel test program on an ogive-cylinder-flare combination to determine the extent of laminar separation as a function of wall temperature for fixed free-stream Reynolds number per unit length at a free-stream Mach number of 8.0. The objective of the tests was to see if separation could be eliminated entirely by cooling the wall to a sufficiently low value. Pressure and temperature distributions spanning the separation region were made on a quick-insertion model, but the location of the separation point could not be obtained during the tests. Accordingly, a combined experimental-theoretical method was developed for determining the separation point location. Correlation of the separation length with model temperature ratio indicated that the separation distance was small and was rapidly approaching zero at the lowest wall temperature ratio achieved experimentally. The apparent critical wall temperature ratio so indicated by the data was lower than the theoretical ratio. It was not possible to achieve sufficiently low temperatures to see if separation could be entirely eliminated. Possible reasons for the difference between experiment and theory are discussed.