Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
A N IMPORTANT question which arises in the consideration of aerodynamic heating problems is that of ascertaining the flight regimes in which nonequilibrium reaction occurs. A general idea of this regime may be gained by an order of magnitude analysis where the characteristic time of reaction is compared to the characteristic residence time, with limiting values of the ratios obtained, arbitrarily assigned. Moreover, such an order of magnitude analysis is useful in those cases where the flow is very far from equilibrium; and recombination may take place, finally, along the surface, since an idea of the wetted area of reaction may be obtained. This type of study is of value in those cases where either catalytic or reaction poisoning surfaces are being considered.In this analysis, the flow field is assumed to be that around a blunt body at hypersonic speeds such that a detached shock exists. The field is divided into two separate regions, each with its own characteristic time. One is the stagnation point flow between the detached shock and the body. The other is the laminar boundary layer flow along the body surface. Each region has a characteristic residence time which is to be compared with the characteristic chemical reaction time.According to Li and Geiger (1) the detachment distance between a detached shock and the stagnation point is, as in Fig.l where k •• Pco/(pS)x=o s = conditions immediately behind the shock R 8a = radius of curvature if the shock at x -0 If, as assumed by Li, the radius of curvature of the shock is the same as that of the body, at x = 0, then b may be calculated. Also, from his calculations, the velocity in the y direction outside the boundary layer is essentially proportional to y; since the v velocity in the boundary layer is well approximated by a linear function, the average velocity in the region between the detached shock and the body along the stagnation streamline is, to good approximation Vavg = Vs/2The residence time in this region is thus[3] The characteristic chemical time consistent with Equation [3] is thenwhere X is any third body and the subscript 2 refers to oxygen atoms. (w 2 ) recombination is that part of the reaction rate which holds for the recombination of oxygen atoms, since this is the essential reaction in the decreasing temperature field. It is calculated using the concentration of 0 and 0 2 existing behind a normal shock, but at the wall temperature. This is a very conservative calculation, since an average temperature between the wave and the body would certainly be higher than the wall temperature, and the recombination rate term is sensitive to changes in temperature. Since no accurate value for the average temperature was known and since it is evident that a linear variation is unrealistic, the conservative value for the reaction rate constant was chosen. For a Shock Boundary / Layer Blunt Body V, Oo Fig. 1 Stagnation point region between a detached shock and a blunt body EDITOR'S NOTE: The Technical Notes and Technical Comments sections of ARS JOURNAL are ...
A N IMPORTANT question which arises in the consideration of aerodynamic heating problems is that of ascertaining the flight regimes in which nonequilibrium reaction occurs. A general idea of this regime may be gained by an order of magnitude analysis where the characteristic time of reaction is compared to the characteristic residence time, with limiting values of the ratios obtained, arbitrarily assigned. Moreover, such an order of magnitude analysis is useful in those cases where the flow is very far from equilibrium; and recombination may take place, finally, along the surface, since an idea of the wetted area of reaction may be obtained. This type of study is of value in those cases where either catalytic or reaction poisoning surfaces are being considered.In this analysis, the flow field is assumed to be that around a blunt body at hypersonic speeds such that a detached shock exists. The field is divided into two separate regions, each with its own characteristic time. One is the stagnation point flow between the detached shock and the body. The other is the laminar boundary layer flow along the body surface. Each region has a characteristic residence time which is to be compared with the characteristic chemical reaction time.According to Li and Geiger (1) the detachment distance between a detached shock and the stagnation point is, as in Fig.l where k •• Pco/(pS)x=o s = conditions immediately behind the shock R 8a = radius of curvature if the shock at x -0 If, as assumed by Li, the radius of curvature of the shock is the same as that of the body, at x = 0, then b may be calculated. Also, from his calculations, the velocity in the y direction outside the boundary layer is essentially proportional to y; since the v velocity in the boundary layer is well approximated by a linear function, the average velocity in the region between the detached shock and the body along the stagnation streamline is, to good approximation Vavg = Vs/2The residence time in this region is thus[3] The characteristic chemical time consistent with Equation [3] is thenwhere X is any third body and the subscript 2 refers to oxygen atoms. (w 2 ) recombination is that part of the reaction rate which holds for the recombination of oxygen atoms, since this is the essential reaction in the decreasing temperature field. It is calculated using the concentration of 0 and 0 2 existing behind a normal shock, but at the wall temperature. This is a very conservative calculation, since an average temperature between the wave and the body would certainly be higher than the wall temperature, and the recombination rate term is sensitive to changes in temperature. Since no accurate value for the average temperature was known and since it is evident that a linear variation is unrealistic, the conservative value for the reaction rate constant was chosen. For a Shock Boundary / Layer Blunt Body V, Oo Fig. 1 Stagnation point region between a detached shock and a blunt body EDITOR'S NOTE: The Technical Notes and Technical Comments sections of ARS JOURNAL are ...
The present paper deals with the general problem of hydroelastic sloshing of a liquid in a partially filled circular cylindrical container with either rigid walls and a flexible flat bottom or a rigid bottom and elastic walls. Free coupling oscillations of the tank‐liquid system are investigated including the effect of surface tension. Forces and moments excerted on the walls by the liquid as well as the form of the free surface are determined. A procedure to investigate approximately the oscillations of the liquid under weak gravitation is outlined.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.