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THE ROLE OF THE TURBULENT VISCOUS SUBLAYER IN THE FORMATION OF SURFACE PATTERNS,
GENERAL ELECTRIC CO PHILADELPHIA PA MISSILE AND SPACE DIV
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An analysis of the compressible viscous turbulent sublayer characteristics as related to the formation of cross-hatched surface patterns of re-entry bodies at hypersonic speeds is presented. Detailed velocity and temperature fluctuation fields are obtained considering the turbulent viscous sublayer to be subjected to pressure fluctuations and turbulence in the outer portions of the turbulent boundary layer with mass transfer at the body surface. Three-dimensional velocity fluctuations are considered which is necessary for the formation of surface patterns. The wave angle of the dominant fluctuations is found to be in reasonable agreement with the pattern angle formed on ablated models. The relation of the disturbance wave angle to surface patterns is discussed further by a breakdown mechanism of the sublayer. Effects of compressibility and density fluctuations have been included. The analysis suggests that the sublayer Reynolds number formed from the friction velocity and disturbance wavelengths would be useful for the correlation of experimental data. Author
APPROVED FOR PUBLIC RELEASE