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A computational investigation of inviscid hypervelocity flow of a dissociating gas past a cone at incidence

Published online by Cambridge University Press:  26 April 2006

M. N. Macrossan
Affiliation:
Department of Mechanical Engineering, University of Queensland, St Lucia, Qld. 4072, Australia
D. I. Pullin
Affiliation:
Graduate Aeronautical Laboratories 105–50, California Institute of Technology, Pasadena CA 91125, USA

Abstract

Calculations have been performed for the inviscid hypervelocity flow of nitrogen past a 15° semi-angle sharp cone at an incidence of 30°, at an enthalpy sufficiently high to produce dissociation/recombination chemistry downstream of the bow shock wave. A spatially second-order-accurate scheme for the numerical solution of the inviscid Euler equations was used combined with the Lighthill–Freeman model of the non-equilibrium ideal dissociating gas. The computational method has been used as a ‘numerical wind tunnel’ in order to gain understanding of the interaction between the gas dynamics and the finite-rate gas chemistry. Inviscid flow has been considered to ensure that the only physical lengthscales in the flow are those associated with the chemical reactions. It was found that a chemical lengthscale Ls based on the local dissociation length behind the shock on the windward plane of symmetry is an important governing parameter of the flow. However, as the flow lengthscale becomes large and the flow approaches the limiting case of equilibrium chemistry, Ls is not the dominant chemical lengthscale. This is particularly true of the leeward flow, which contains a shock–vortex structure. A simple modelling technique has been used to determine a more appropriate lengthscale, Lr, t, for the leeward flow as the equilibrium limit is approached. This lengthscale is based on the expected equilibrium conditions behind the cross-flow shock.

Type
Research Article
Copyright
© 1994 Cambridge University Press

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References

Freeman, N. C. 1958 Non-equilibrium flow of an ideal dissociating gas. J. Fluid Mech. 4, 407.Google Scholar
Hornung, H. G. 1972 Non-equilibrium dissociating nitrogen flow over spheres and circular cylinders. J. Fluid Mech. 53, 149.Google Scholar
Hornung, H. G. 1976 Non-equilibrium ideal dissociation after a curved shock wave. J. Fluid Mech. 74, 143.Google Scholar
Hornung, H. G. 1988 Experimental real-gas hypersonics. Aero. J. 92, 379.Google Scholar
Kewley, D. J. & Hornung, H. G. 1974 Free-piston shock-tube study of nitrogen dissociation. Chem. Phys. Lett. 25, 531.Google Scholar
Krek, R., Hannemann, K. & Pullin, D. I. 1989 Real gas effects in hypervelocity flows over an inclined cone. In 10 AFMC, University of Melbourne, Paper 12C-1. (ed. A. E. Perry). University of Melbourne.
Leer, B. van 1979 Towards the ultimate conservative difference scheme, Part V. J. Comput. Phys. 32, 101.Google Scholar
Lighthill, M. J. 1957 Dynamics of a dissociating gas. Part 1. Equilibrium flow. J. Fluid Mech. 2, 1.Google Scholar
Macrossan, M. N. 1989 The equilibrium flux method for the calculation of flows with non-equilibrium chemical reactions. J. Comput. Phys. 80, 204.Google Scholar
Macrossan, M. N. 1990 Hypervelocity flow of dissociating nitrogen downstream of a blunt nose. J. Fluid Mech. 217, 167.Google Scholar
Macrossan, M. N. & Pullin, D. I. 1990 Hypervelocity cone-flow with reaction chemistry by a second order kinetic theory based Euler solver. In Third Austral. Supercomputer Conf., University of Melbourne December 1990. (ed. K. Sweeny). Strategic Research Foundation, University of Melbourne.
Macrossan, M. N., Pullin, D. I. & Richter, N. J. 1989 Calculations of three-dimensional hypervelocity cone-flow with chemical reactions. In 10 AFMC, University of Melbourne, Paper 12C-3. (ed. A. E. Perry). University of Melbourne.
Marconi, F. 1989 Complex shock patterns and vortices in inviscid supersonic flows. Comput. Fluids 17, 151.Google Scholar
Pullin, D. I. 1980 Direct simulation methods for compressible ideal gas flow. J. Comput. Phys. 34, 231.Google Scholar
Stalker, R. J. 1989 Approximations for non-equilibrium hypervelocity aerodynamics. Ann. Rev. Fluid Mech. 21, 37.Google Scholar
Yee, H. C. 1989 A class of high-resolution explicit and implicit shock-capturing methods. NASA Tech. Mem. 101088.