Morphology of a standing oblique detonation wave

Pratt, David T.; Humphrey, Joseph W.; Glenn, Dennis E.

doi:10.2514/6.1987-1785

Cited by 29 publications

(5 citation statements)

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“…2. The gas dynamic principles of the ODRA are similar to those of the oblique detonation wave engine (Ostrander et al 1987;Pratt et al 1987) which has been proposed as an alternative to the scramjet engine for propelling hypersonic air-breathing vehicles. Other propulsive modes capable of operating at superdetonative speeds have been suggested.…”

Section: Introductionmentioning

confidence: 77%

Experimental investigation of ram accelerator propulsion modes

1991

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Abstract. Experimental investigations on tile propulsive modes of the ram accelerator are reviewed in this paper. The ram accelerator is a ramjet-in-tube projectile accelerator whose principle of operation is similar to that of a supersonic air-breathing ramjet. The projectile resembles the centerbody of a ramjet and travels through a stationary tube filled with a premixed gaseous fuel and oxidizer mixture. The combustion process travels with the projectile, generating a pressure distribution which produces forward thrust on the projectile. Several modes of ram accelerator operation are possible which are distinguished by their operating velocity range and the manner in which the combustion process is initiated and stabilized. Propulsive cycles utilizing subsonic, thermally choked combustion theoretically allow projectiles to be accelerated to the Chapman-aouguet(C-J) detonation speed of a gaseous propellant mixture. In the superdetonative velocity range, the projectile is accelerated while always traveling faster than the C-J speed, and in the transdetonative regime (85-115 % of C-J speed) the projectile makes a smooth transition from a subdetonative to a superdetonative propulsive mode. This paper examines operation in these three regimes of flow using methane and ethylene based propellant mixtures in a 16 rn long, 38 mm bore ram accelerator using 45-90 g projectiles at velocities tap to 2500 m/s.

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Section: Introductionmentioning

confidence: 77%

Experimental investigation of ram accelerator propulsion modes

1991

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“…Equations (1)(2)(3)(4)(5)(6)(7)(8)(9) have been scaled such that in the f ( f-+ 0) the postshock pressure, density, and velocities are all 0(1) quantities. The lengths have been scaled by the reaction zone length.…”

Section: C=h•mentioning

confidence: 99%

“…The studies of Vincenti 1 , which presents closedform solutions to linearized equations for nonequilibrium flow over a thin wedge, Capiaux and Washington 2 , which gives a numerical solution based on the method of characteristics for non-equilibrium flow over a thick wedge, and Lee 3 , which presents a closed-form solution for non-equilibrium flow over a thick wedge, are representative of many early studies. With the renewed interest in several hypervelocit.y devices such as the oblique detonation wave engine 4 (ODWE), the ram accelerator 5 , and the advanced hypervelocity aerophysics facility 6 (AHAF), many recent studies have appeared . Among these are those of Bogdanoff and Brackett 7 , Fujiwara, et al 8 , \Vang, et al 9 , Cambier, et al 10 • 11 , Yungster 12 • 13 , and Pandolfi, et aJ.l 4 With the exception of the work of Pandolfi, et a!., which utilizes the method of characteristics, these studies employ numerical techniques to directly solve the governing partial differential equations.…”

Section: Introductionmentioning

confidence: 99%

“…With the renewed interest in several hypervelocit.y devices such as the oblique detonation wave engine 4 (ODWE), the ram accelerator 5 , and the advanced hypervelocity aerophysics facility 6 (AHAF), many recent studies have appeared . Among these are those of Bogdanoff and Brackett 7 , Fujiwara, et al 8 , \Vang, et al 9 , Cambier, et al 10 • 11 , Yungster 12 • 13 , and Pandolfi, et aJ.l 4 With the exception of the work of Pandolfi, et a!., which utilizes the method of characteristics, these studies employ numerical techniques to directly solve the governing partial differential equations. •In addition a number of related fundamental and applied studies are cited in the recent book by Anderson 15 , which also gives a relevant general discussion.…”

Section: Introductionmentioning

confidence: 99%

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Comparisons of numerical and exact solutions for oblique detonationswith structure

Powers

Grismer

1991

22nd Fluid Dynamics, Plasma Dynamics and Lasers Conference

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Numerical predictions of the two-dimensional, inviscid, supersonic, reactive flow of a calorically perfect ideal gas over a straight wedge are compared with the predictions of a linear asymptotic model valid in the hypersonic limit. Solution features predicted by the asymptotic model include a curved shock attached to the wedge tip, a reaction layer parallel to the shock, and a vorticity layer parallel to the wedge surface. For sufficiently high Mach number and heat release, the numerical model predicts similar behavior, and the differences in the predictions of the two methods are of the same order of magnitude as the inherent error of the asymptotic method. As heat release is lowered and Mach number held constant, apparent numerical artifacts obscure features predicted by the asymptotic method. The results suggest that the asymptotic solution has utility as a benchmark to verify the predictions of many high-speed, multidimensional, reacting flow codes.

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“…Several give a RankineHugoniot (RH) analysis of oblique detonations: e.g. (Siestrunck, et al, 1953), (Larisch, 1959), (Gross, 1963), (Oppenheim, et al, 1968), (Chernyi, 1969), (Buckmaster and Lee, 1990), and (Pratt, et al, 1991). Other analyses are for either steady two-dimensional or unsteady one-dimensional flows with spatially resolved structure; many of these focus on the related topic of dissociation and vibrational relaxation: e.g.…”

Section: Reviewmentioning

confidence: 99%

Oblique Detonations: Theory and Propulsion Applications

Powers

1994

ICASE/LaRC Interdisciplinary Series in Science and Engineering

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The oblique detonation, a combustion process initiated by an oblique shock, arises in most supersonic combustion applications including, most notably, the ram accelerator and the oblique detonation wave engine. Additionally, it is the generic two-dimensional compressible shocked reacting flow; consequently, its basic research value is inherent. The outstanding theoretical questions are also the fundamental practical questions: e.g. what conditions are necessary for steady solutions, what is the dependency of the steady propagation speed on the ambient condition, what is the susceptibility of the system to instability, and what is the behavior of the system in unsteady operation. A related topic which transcends all questions is the ability to describe these phenomena computationally. At this early stage, these issues are most clearly addressed with simple models. This paper will review the application of such models to oblique detonations and discuss their future relevance.

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Morphology of a standing oblique detonation wave

Cited by 29 publications

References 0 publications

Experimental investigation of ram accelerator propulsion modes

Experimental investigation of ram accelerator propulsion modes

Comparisons of numerical and exact solutions for oblique detonationswith structure

Oblique Detonations: Theory and Propulsion Applications

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