Author: John David Anderson (Jr.)
Publisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 84
Book Description
Results are presented for several numerical experiments using an analysis of the viscous radiating stagnation region shock layer and stagnation point heat transfer. A simple step model absorption coefficient, rationally constructed from existing quantum mechanical calculations, is shown to accurately predict shock layer nongray continuum radiative heat transfer in comparison to results obtained with detailed spectral absorption coefficients. Sensitivity of the heat transfer to uncertainties in gas radiative and transport properties is also examined, as well as the effect of artificially increased absorption in the boundary layer. (Author).
Stagnation Point Heat Transfer from a Viscous Nongray Radiating Shock Layer
Author: John David Anderson (Jr.)
Publisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 84
Book Description
Results are presented for several numerical experiments using an analysis of the viscous radiating stagnation region shock layer and stagnation point heat transfer. A simple step model absorption coefficient, rationally constructed from existing quantum mechanical calculations, is shown to accurately predict shock layer nongray continuum radiative heat transfer in comparison to results obtained with detailed spectral absorption coefficients. Sensitivity of the heat transfer to uncertainties in gas radiative and transport properties is also examined, as well as the effect of artificially increased absorption in the boundary layer. (Author).
Publisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 84
Book Description
Results are presented for several numerical experiments using an analysis of the viscous radiating stagnation region shock layer and stagnation point heat transfer. A simple step model absorption coefficient, rationally constructed from existing quantum mechanical calculations, is shown to accurately predict shock layer nongray continuum radiative heat transfer in comparison to results obtained with detailed spectral absorption coefficients. Sensitivity of the heat transfer to uncertainties in gas radiative and transport properties is also examined, as well as the effect of artificially increased absorption in the boundary layer. (Author).
Stagnation Point Heat Transfer from a Viscous Nongray Radiating Shock Layer, Including the Applicability of Step Model Absorption Coefficients and Sensitivity to Uncertainties in Transport Properties
Author: John D Anderson (Jr)
Publisher:
ISBN:
Category :
Languages : en
Pages : 52
Book Description
Results are presented for several numerical experiments using an analysis of the viscous radiating stagnation region shock layer and stagnation point heat transfer. A simple step model absorption coefficient, rationally constructed from existing quantum mechanical calculations, is shown to accurately predict shock layer nongray continuum radiative heat transfer in comparison to results obtained with detailed spectral absorption coefficients. Sensitivity of the heat transfer to uncertainties in gas radiative and transport properties is also examined, as well as the effect of artificially increased absorption in the boundary layer. (Author).
Publisher:
ISBN:
Category :
Languages : en
Pages : 52
Book Description
Results are presented for several numerical experiments using an analysis of the viscous radiating stagnation region shock layer and stagnation point heat transfer. A simple step model absorption coefficient, rationally constructed from existing quantum mechanical calculations, is shown to accurately predict shock layer nongray continuum radiative heat transfer in comparison to results obtained with detailed spectral absorption coefficients. Sensitivity of the heat transfer to uncertainties in gas radiative and transport properties is also examined, as well as the effect of artificially increased absorption in the boundary layer. (Author).
Technical Abstract Bulletin
Radiative Gas Dynamics
Author: Robert Goulard
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 136
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 136
Book Description
Stagnation Point Analysis of Coupled Viscous-radiating Flow with Massive Blowing
Author: K. H. Wilson
Publisher:
ISBN:
Category : Ablation (Aerothermodynamics)
Languages : en
Pages : 108
Book Description
This report presents an analysis of the fully coupled viscous, radiating flow at the stagnation point of an ablating blunt body at hyperbolic entry conditions. An exact numerical solution to the momentum equation has been developed which replaces the integral method employed in previous studies.
Publisher:
ISBN:
Category : Ablation (Aerothermodynamics)
Languages : en
Pages : 108
Book Description
This report presents an analysis of the fully coupled viscous, radiating flow at the stagnation point of an ablating blunt body at hyperbolic entry conditions. An exact numerical solution to the momentum equation has been developed which replaces the integral method employed in previous studies.
A Theoretical Study of Stagnation-point Ablation
Author: Leonard Roberts
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 20
Book Description
A simplified analysis is made of ablation cooling near the stagnation point of a two-dimensional or axisymmetric body which occurs as the body vaporizes directly from the solid state. The automatic shielding mechanism is discussed and the important thermal properties required by a good ablation material are given. The results of the analysis are given in terms of dimensionless parameters.
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 20
Book Description
A simplified analysis is made of ablation cooling near the stagnation point of a two-dimensional or axisymmetric body which occurs as the body vaporizes directly from the solid state. The automatic shielding mechanism is discussed and the important thermal properties required by a good ablation material are given. The results of the analysis are given in terms of dimensionless parameters.
Reacting Viscous-shock-layer Solutions with Multicomponent Diffusion and Mass Injection
Author: James N. Moss
Publisher:
ISBN:
Category : Shock waves
Languages : en
Pages : 156
Book Description
This study presents numerical solutions of the viscous-shock-layer equations where the chemistry is treated as being either frozen, equilibrium, or nonequilibrium. Also the effects of the diffusion model, surface catalysis, and mass injection on surface transport and flow parameters are considered. The flow is treated as a mixture of five inert and thermally perfect species. The viscous-shock-layer equations are solved by using an implicit-difference scheme. All calculations are for hyperboloids with included angles of 20° and 45°. The flight conditions are those for various altitudes and velocities in the Earth's atmosphere. Data are presented to show the effects of the chemical models; diffusion models; surface catalysis; and mass injection of air on heat transfer; skin friction; shock standoff distance; wall pressure distribution; and tangential victory, temperature, and species profiles. The results show that an equilibrium analysis can substantially overpredict the heat-transfer rates for flow conditions experienced by earth-orbital entry vehicles. Moreover, at such conditions surface catalysis significantly influences heat-transfer and flow-field properties. If a binary rather than a multicomponent diffusion model is assumed, negligible errors in most flow properties result. Quantitative results are presented that show the effect of mass injection on flow properties within and downstream of the injection region.
Publisher:
ISBN:
Category : Shock waves
Languages : en
Pages : 156
Book Description
This study presents numerical solutions of the viscous-shock-layer equations where the chemistry is treated as being either frozen, equilibrium, or nonequilibrium. Also the effects of the diffusion model, surface catalysis, and mass injection on surface transport and flow parameters are considered. The flow is treated as a mixture of five inert and thermally perfect species. The viscous-shock-layer equations are solved by using an implicit-difference scheme. All calculations are for hyperboloids with included angles of 20° and 45°. The flight conditions are those for various altitudes and velocities in the Earth's atmosphere. Data are presented to show the effects of the chemical models; diffusion models; surface catalysis; and mass injection of air on heat transfer; skin friction; shock standoff distance; wall pressure distribution; and tangential victory, temperature, and species profiles. The results show that an equilibrium analysis can substantially overpredict the heat-transfer rates for flow conditions experienced by earth-orbital entry vehicles. Moreover, at such conditions surface catalysis significantly influences heat-transfer and flow-field properties. If a binary rather than a multicomponent diffusion model is assumed, negligible errors in most flow properties result. Quantitative results are presented that show the effect of mass injection on flow properties within and downstream of the injection region.
Stagnation Point Solution of Viscous Shock Layer Equations for Flow Past a Sphere
Author: B. N. Srivastava
Publisher:
ISBN:
Category :
Languages : en
Pages : 34
Book Description
Numerical solutions in the stagnation region of a spherically blunted body are obtained by using the full and thin layer version of the viscous shock layer equations. The numerical system utilizes an implicit finite difference scheme combined with a relaxation technique for determining the bow shock shape. Comparisons with experimental data are made for shock Reynolds numbers, Re sub s, of 20 to 2000 and Mach numbers of 4 to 20. Both the surface heating levels as well as the shock layer density profiles are presented. It is found that with the inclusion of the shock and body slip, the full viscous shock layer model apparently enjoys a range of validity down to Re sub s of 20 to 30. The thin layer version of these equations are shown to be inadequate for such low Reynolds numbers. (Author).
Publisher:
ISBN:
Category :
Languages : en
Pages : 34
Book Description
Numerical solutions in the stagnation region of a spherically blunted body are obtained by using the full and thin layer version of the viscous shock layer equations. The numerical system utilizes an implicit finite difference scheme combined with a relaxation technique for determining the bow shock shape. Comparisons with experimental data are made for shock Reynolds numbers, Re sub s, of 20 to 2000 and Mach numbers of 4 to 20. Both the surface heating levels as well as the shock layer density profiles are presented. It is found that with the inclusion of the shock and body slip, the full viscous shock layer model apparently enjoys a range of validity down to Re sub s of 20 to 30. The thin layer version of these equations are shown to be inadequate for such low Reynolds numbers. (Author).
The Effect of Radiative Emission and Self-absorption on the Flow Field and Heat Transfer Behind a Reflected Shock Wave of Air
Author: John David Anderson
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 284
Book Description
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 284
Book Description
Stagnation Point Boundary Layer with Large Wall-to-freestream Enthalpy Ratio
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
The effect of large surface-to-freestream enthalpy ratios on stagnation point shear and heat transfer is investigated for two-dimensional and axisymmetric bodies. Numerical solutions are obtained for a wide range of enthalpy ratios and wall transpiration rates. Absorption of externally imposed thermal radiation by the transpired gas is included for cases where the absorption is small compared to thermal conduction. It is found that the pressure gradient causes large velocity overshoot in the boundary layer. In the limit of infinite enthalpy ratio. the peak velocity in the boundary layer is approximately 4/9 or 1/3 that value that would occur at the wall for an inviscid two-dimensional or axisymmetric flow, respectively, with the same temperature ratio. The application of the numerical results to 'cold flow plus radiation' nose-tip test facilities is also noted. (Author).
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
The effect of large surface-to-freestream enthalpy ratios on stagnation point shear and heat transfer is investigated for two-dimensional and axisymmetric bodies. Numerical solutions are obtained for a wide range of enthalpy ratios and wall transpiration rates. Absorption of externally imposed thermal radiation by the transpired gas is included for cases where the absorption is small compared to thermal conduction. It is found that the pressure gradient causes large velocity overshoot in the boundary layer. In the limit of infinite enthalpy ratio. the peak velocity in the boundary layer is approximately 4/9 or 1/3 that value that would occur at the wall for an inviscid two-dimensional or axisymmetric flow, respectively, with the same temperature ratio. The application of the numerical results to 'cold flow plus radiation' nose-tip test facilities is also noted. (Author).