Blunt-body Stagnation-region Flow with Nongray Radiation Heat Transfer
Blunt-body Stagnation-region Flow with Nongray Radiation Heat Transfer

Author: Walter B. Olstad

Publisher:

Published: 1968

Total Pages: 92

ISBN-13:

DOWNLOAD EBOOK

A singular perturbation solution to the blunt-body stagnation-region flow of an inviscid, radiating gas has been obtained by means of the Poincař-Lighthill-Kuo, or perturbation-of-coordinates, method. A number of results for a gray gas have been presented in order to provide some physical insight into the effects of various parameters on the shock-layer enthalpy profiles and the radiant heat-transfer rates. A nongray absorption-coefficient model was developed which includes, in an approximate way, the important vacuum-ultraviolet contributions of bound-free and line transitions. This model was used to obtain solutions pertinent to the case of reentry into the earth's atmosphere. While the results are restricted to small values of the radiation cooling parameter, which characterizes the relative importance of radiation and convection as energy-transport mechanisms, they cover broad ranges of vehicle velocity, altitude, and nose radius, which are of practical interest. The characteristic enthalpy variation of the model absorption coefficient was found to be nearly independent of altitude and nose radius for fixed vehicle velocity except for velocities lower than 10.67 km/sec. Thus it was possible to correlate certain quantities by plotting these quantities as functions of the nondimensional adiabatic radiant heat-transfer rate for various altitudes and nose radii at fixed vehicle velocity. Among the quantities correlated was the cooling factor (the ratio of the stagnation-point radiant heat-transfer rate to the adiabatic radiant heat-transfer rate). The cooling-factor correlation is particularly useful because it eliminates the need to perform nonadiabatic calculations whenever radiant heat-transfer rates are desired. Also correlated was the factor by which the convective heat-transfer rate is reduced because of radiation losses in the shock layer. Finally, upper-bound estimates were made of the effects of absorption of precursor radiation by the free-stream air on the radiant and convective heat-transfer rates.

The Blunt-body Problem in Hypersonic Flow at Low Reynolds Number
The Blunt-body Problem in Hypersonic Flow at Low Reynolds Number

Author: H. K. Cheng

Publisher:

Published: 1963

Total Pages: 136

ISBN-13:

DOWNLOAD EBOOK

Existing theoretical analyses and experimental results of the stagnation region in hypersonic flow at low Reynolds number are discussed. The approach based on the thin-shock-layer approxi mation is extended to study flow fields beyond the stagnation region as well as in the shock transition zone. The basic flow model consists of two adjoining thin layers: a shock-transition zone and a shock layer. The system of partial differential equations governing the high-density shock layer reduces to the parabolic type. The system governing the shock-transition zone reduces to ordinary differential equations similar to those of the one-dimensional shock wave. They give rise to a set of conservation relations across the shock, which account for the transport processes immediately behind the shock but do not involve details of shock-wave structure. With the modified Rankine-Hugoniot relations, the flow field in shock layer can be determined independ ently of the shock-transition zone. An essential feature of this formulation is that, when applied in conjunction with nonslip surface conditions, it always yields the appropriate surface heat transfer rate and skin friction (for unit accommo dation coefficients) in the free-molecule limit. (Author).

Heat Transfer and Boundary-layer Transition on Two Blunt Bodies at Mach Number 3.12
Heat Transfer and Boundary-layer Transition on Two Blunt Bodies at Mach Number 3.12

Author: N. S. Diaconis

Publisher:

Published: 1957

Total Pages: 31

ISBN-13:

DOWNLOAD EBOOK

Local heat-transfer parameters were measured on a hemisphere-cone-cylinder and on a 120 degree-included-angle cone-cylinder at a free-stream Mach number of 3.12 and at free-stream unit Reynolds numbers as high as 1,292.000 per inch. Heat-transfer data are presented for the case of wall temperature approximat&ly equal to free-stream static temperature.

Shock Wave-Boundary-Layer Interactions
Shock Wave-Boundary-Layer Interactions

Author: Holger Babinsky

Publisher: Cambridge University Press

Published: 2011-09-12

Total Pages: 481

ISBN-13: 1139498649

DOWNLOAD EBOOK

Shock wave-boundary-layer interaction (SBLI) is a fundamental phenomenon in gas dynamics that is observed in many practical situations, ranging from transonic aircraft wings to hypersonic vehicles and engines. SBLIs have the potential to pose serious problems in a flowfield; hence they often prove to be a critical - or even design limiting - issue for many aerospace applications. This is the first book devoted solely to a comprehensive, state-of-the-art explanation of this phenomenon. It includes a description of the basic fluid mechanics of SBLIs plus contributions from leading international experts who share their insight into their physics and the impact they have in practical flow situations. This book is for practitioners and graduate students in aerodynamics who wish to familiarize themselves with all aspects of SBLI flows. It is a valuable resource for specialists because it compiles experimental, computational and theoretical knowledge in one place.