Assessment of a Transitional Boundary Layer Theory at Low Hypersonic Mach Numbers
Assessment of a Transitional Boundary Layer Theory at Low Hypersonic Mach Numbers

Author: S. J. Shamroth

Publisher:

Published: 1972

Total Pages: 76

ISBN-13:

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An investigation was carried out to assess the accuracy of a transitional boundary layer theory in the low hypersonic Mach number regime. The theory is based upon the simultaneous numerical solution of the boundary layer partial differential equations for the mean motion and an integral form of the turbulence kinetic energy equation which controls the magnitude and development of the Reynolds stress. Comparisions with experimental data show the theory is capable of accurately predicting heat transfer and velocity profiles through the transitional regime and correctly predicts the effects of Mach number and wall cooling on transition Reynolds number. The procedure shows promise of predicting the initiation of transition for given free stream disturbance levels. The effects on transition predictions of the pressure dilitation term and of direct absorption of acoustic energy by the boundary layer were evaluated.

A Nonlinear Theory for Predicting the Effects of Unsteady Laminar, Turbulent, Or Transitional Boundary Layers on the Attenuation of Shock Waves in a Shock Tube with Experimental Comparison
A Nonlinear Theory for Predicting the Effects of Unsteady Laminar, Turbulent, Or Transitional Boundary Layers on the Attenuation of Shock Waves in a Shock Tube with Experimental Comparison

Author: Robert L. Trimpi

Publisher:

Published: 1958

Total Pages: 682

ISBN-13:

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The linearized attenuation theory of NACA Technical Note 3375 is modified in the following manner: (a) an unsteady compressible local skin-friction coefficient is employed rather than the equivalent steady-flow incompressible coefficient; (b) a nonlinear approach is used to permit application of the theory to large attenuations; and (c) transition effects are considered. Curves are presented for predicting attenuation for shock pressure ratios up to 20 and a range of shock-tube Reynolds numbers. Comparison of theory and experimental data for shock wave strengths between 1.5 and 10 over a wide range of Reynolds numbers shows good agreement with the nonlinear theory evaluated for a transition Reynolds nuniber of 2.5 million.