Transition on a sharp cone at high enthalpy - New measurements in the shock tunnel T5 at GALCITAn exploratory study of the laminar, transitional and turbulent boundary layer on a slender cone in hypervelocity flow was conducted in the high-enthalpy shock tunnel T5. A novel flow visualization technique using sodium seeding to increase the sensitivity of conventional interferometric techniques by resonant enhancement of the refractivity of the medium was developed to study its structure. The experiments were designed to cover a large range of specific reservoir enthalpy, ranging from the perfect-gas region to the range where significant oxygen and some nitrogen dissociation and recombination effects may be expected in the boundary layer. Surface heat flux measurements indicate that the transition Reynolds number is approximately the same as that observed in cold hypersonic flow in conventional continuous flow facilities, but significantly lower than that observed in 'quiet' tunnels. No significant effect of reservoir specific enthalpy on transition was observed. The heat flux distribution showed differences between the air and the nitrogen experiments in the laminar regime. These are consistent with the presence of recombination of oxygen at the wall. This view is supported by the fact that this effect is absent in the low-enthalpy region, where the heat flux distribution agrees with the similarity theory.
Document ID
19930039033
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Germain, P. (NASA Langley Research Center Hampton, VA, United States)
Cummings, E. (NASA Langley Research Center Hampton, VA, United States)
Hornung, H. (California Inst. of Technology Pasadena, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1993
Subject Category
Aerodynamics
Report/Patent Number
AIAA PAPER 93-0343
Meeting Information
Meeting: AIAA, Aerospace Sciences Meeting and Exhibit