An Approximate Method for the Calculation of the Reynolds Analogy Factor for a Compressible Turbulent Boundary Layer in a Pressure Gradient


Book Description

The method predicts that a positive pressure gradient increases and a negative pressure gradient decreases the ratio of Stanton number to friction coefficient. The Crocco relation between the velocity and total enthalpy for a non-adiabatic surface and zero pressure gradient is generalized to non-zero pressure gradient. The relation between the velocity and the total enthalpy varies markedly from the flat plate Crocco relation as the pressure gradient departs from zero. The magnitude of the variation depends on the velocity profile shape parameter. (Author).




Approximate Calculation of the Compressible Turbulent Boundary Layer with Heat Transfer and Arbitrary Pressure Gradient


Book Description

The method, as applied to insulated surfaces, is quite well founded but, for noninsulated isothermal surfaces, depends on a number of speculative assumptions. These assumptions are qualitatively proper, and it is hoped that they will yield reasonable quantitative results. The detailed application of the method for practical calculations is described.
















Approximations for the Thermodynamic and Transport Properties of High-temperature Air


Book Description

The thermodynamic and transport prorerties of high-temperature air are found in closed form starting from approximate partition functions for the major components in air and neglecting all minor components. The compressibility, energy, entropy, the specific heats, the speed of sound, the coefficients of viscosity and of thermal conductivity, and the Prandtl numbers for air are tabulated from 500 degrees to 15,000 degrees K over a range of pressure from 0.0001 to 100 atmospheres. The enthalpy of air and the mol fractions of the major components of air can easily be found from the tabulated values for compressibility and energy. It is predicted that the Prandtl number for fully ionized air will become small compared to unity, the order of 0.01, and this implies that boundary layers in such flow will be very transparent to heat flux.




A Method of Calculating Turbulent-boundary-layer Growth at Hypersonic Mach Numbers


Book Description

A method is developed for calculating the growth of a turbulent boundary layer at hypersonic Mach numbers. Excellent agreement with experimental results from axisymmetric nozzles has been obtained by the application of this method. The method utilizes a modification of Stewartson's transformation to simplify the integration of the momentum equation. Heat transfer is taken into account by evaluating the gas properties at Eckert's reference temperature and by using a modification of Crocco's quadratic for the temperature distribution in the boundary layer. A new empirical relation is used for the incompressible friction coefficient which agrees with experimental data over a Reynold's number range from 10(superscript 5) to 10(superscript 9).




NASA Technical Note


Book Description