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An investigation of shock strengthening in a conical convergent channel

Published online by Cambridge University Press:  29 March 2006

Robert E. Setchell
Affiliation:
Graduate Aeronautical Laboratories, California Institute of Technology
Erik Storm
Affiliation:
Graduate Aeronautical Laboratories, California Institute of Technology
Bradford Sturtevant
Affiliation:
Graduate Aeronautical Laboratories, California Institute of Technology

Abstract

The behaviour of an initially plane, strong shock wave propagating into a conical convergence is investigated experimentally and theoretically. In the experiment a 10° half-angle cone is mounted on the end of a pressure-driven shock tube. Shock waves with initial Mach numbers varying from 6.0 to 10·2 are generated in argon a t a pressure of 1·5 Torr. During each run local shock velocities a t several positions along the cone axis are measured using a thin multi-crystal piezoelectric probe inserted from the vertex. This technique produces accurate velocity data for both the incident and reflected shock waves. In the corresponding analysis, a simplified characteristics method is used to obtain an approximate solution of the axisymmetric diffraction equations derived by Whitham (1959).

Both the shock velocity measurements and the axisymmetric diffraction solution confirm that the incident shock behaviour is dominated by cyclic diffraction processes which originate at the entrance of the cone. Each diffraction cycle is characterized by Mach reflexion on the cone wall followed by Mach reflexion on the axis, These cycles evidently persist until the shock reaches the cone vertex, where the measured velocity has increased by as much as a factor of three. Real-gas effects, enhanced in the experiment by increasing the initial Mach number and decreasing the pressure, apparently alter the shock wave behaviour only in the region near the vertex. Velocity measurements for the reflected shock within the cone show that the shock velocity is nearly constant throughout most of the convergence length.

Type
Research Article
Copyright
© 1972 Cambridge University Press

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References

Arave, R. & Huseby, O. 1962 Boeing Rep. D2-11238.
Belokin, V. A., Petrukhin, A. I. & Proskuryakov, V. A. 1965 Soviet Phys. J.E.T.P. (Eng. Trans.) 21, 33.
Bird, G. A. 1959 J. Fluid Mech. 5, 60.
Butler, D. S. 1954 Armament Res. Establishment Rep. 54/54.
Chester, W. 1954 Phil. Mag. 45 (7), 1293.
Chester, W. 1960 Adiv. Appl. Mech 6, 120.
Crisnell, R. F. 1957 J. Fluid Mech. 2, 286.
Guderley, G. 1942 Lufifahrtforschung, 19, 302.
LAU, J. 1971 C.A.X.I. Trans. 4, 13.
Mcewan, A. D. 1968 Australian Def. Sci. Serv. Aero. Note no. 298.
Milton, B. E. & Archer, E. D. 1969 A.I.A.A. J. 7, 779.
Russell, D. A. 1967 J. Fluid Mech. 27, 305.
Setchell, R. E. 1971 Ph.D. thesis, California Institute of Technology.
Skews, B. W. 1972 A.I.A.A. J. 10, 839.
Smith, J. A. 1967 Ph.D. thesis, California Institute of Technology.
Whitham, G. B. 1957 J. Fluid Mech 2, 145.
Whitham, G. B. 1958 J. Fluid Mech. 4, 337.
Whitham, G. B. 1959 J. Fluid Mech. 5, 369.