Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-21T17:22:01.703Z Has data issue: false hasContentIssue false
  • English
  • Français

An update on non-stationary oblique shock-wave reflections: actual isopycnics and numerical experiments

Published online by Cambridge University Press:  20 April 2006

R. L. Deschambault  and
I. I. Glass
R. L. Deschambault
Affiliation:
Institute for Aerospace Studies, University of Toronto, 4925 Dufferin Street, Downsview, Ontario, Canada M3H 5T6
I. I. Glass
Affiliation:
Institute for Aerospace Studies, University of Toronto, 4925 Dufferin Street, Downsview, Ontario, Canada M3H 5T6
Get access Rights & Permissions [Opens in a new window]

Abstract

Nonstationary oblique shock-wave reflections over compressive wedges in air and argon were investigated using infinite-fringe interferometric techniques. These allowed direct, continuous and accurate observations of the isopycnics (lines of constant density) of the flow field. The initial pressures for these experiments were made as high as possible (15 to 250 torr) in order to increase the number of isopycnics and to enhance their details and distribution along the wedge surface over a shock-Mach-number range 2.0 < Ms [les ] 8.7. Included in the study were two cases of regular reflection (RR) and one of each single Mach reflection (SMR), complex Mach reflection (CMR) and double-Mach reflection (DMR) for air, and one RR, SMR, CMR and DMR for argon. These particular cases, which we investigated previously in N2 and Ar using a finite-fringe technique, have been used by computational fluid dynamicists to check their finite-difference results against our experimental data. It will be shown that the isopycnic structure previously reported by us differs in detail, in most cases, from that of the present study. The major difference arises from the fact that it was only possible previously to obtain discrete points on isopycnics and along the wedge surface. Consequently, the results obtained before were not as accurate. Comparisons were made of actual wall-density distributions with numerical simulations of the density contours of the various flows obtained by a number of authors. Each numerical method displays its advantages and disadvantages in describing the details of the flow fields. The present experimental results for air are new. They are of great interest from a practical viewpoint. The experiments in argon were redone to provide better data for a gas free from real-gas effects in the range of initial conditions considered, in order to simplify the computations in the numerical simulations. Although the recent numerical simulations are better than those reported previously, additional efforts are required to improve the predictions of the shape, location and values of the isopycnics and other flow isolines in the various regions and along the wall, and to render the predictions free of computer ‘noise’. It is worth noting that real-gas effects did not play any significant role in determining the various wave systems in RR, SMR, CMR and DMR; a different claim was made in our previous work. Relaxation of nitrogen in air can be seen however, at the highest shock Mach numbers (Ms = 7.19 and 8.70), with relaxation lengths in good agreement with accepted predictions.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 131 , June 1983 , pp. 27 - 57
Copyright
© 1983 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Ando, S. 1981 UTIAS Tech. Note no. 231.
Ando, S. & Glass, I. I. 1981 In Proc. 7th Intl Symp. on Military Aspects of Blast Simulation, vol. I, pp. 3.6–1–3.6–24.
Ben-Dor, G. & Glass, I. I. 1978 AIAA J. 16, 1146–1153.
Ben-Dor, G. & Glass, I. I. 1979 J. Fluid Mech. 92, 459–496.
Ben-Dor, G. & Glass, I. I. 1980 J. Fluid Mech. 96, 735–756.
Ben-Dor, G., Written, B. T. & Glass, I. I. 1979 Int. J. Heat Fluid Flow 1, 77–91.
Bleakney, W. & Taub, A. H. 1949 Rev. Mod. Phys. 21, 584–605.
Booen, W. B. & Needham, C. E. 1981 AFWL Tech. Note NTE-TN-81–001.
Book, D., Boris, J., Kuhl, A., Oran, E., Picone, M. & Zalensak, S. 1981 In Proc. 8th Intl Conf. on Numerical Methods in Fluid Dynamics (ed. W. C. Reynolds & R. W. MacCormack). Lecture Notes in Physics, vol. 141, pp. 84–90. Springer.
Champrey, J. M., Chaussee, D. S. & Kutler, P. 1982 AIAA Paper 82–0227.
Colella, P. & Glaz, H. M. 1982 In Proc. 8th Intl Conf. on Numerical Methods in Fluid Dynamics (ed. E. Krause). Lecture Notes in Physics, vol. 170, pp. 175–182. Springer.
Deschambault, R. L. 1983 UTIAS Rep. no. 270.
Fry, M., Titsworth, J., Kuhl, A., Book, D., Boris, J. & Picone, M. 1981 In Proc. 13th Intl Symp. on Shock Tubes and Waves (ed. C. E. Treanor & J. G. Hall), pp. 376–384. State University of New York Press.
Kutler, P. & Shankar, V. S. 1977 AIAA J. 5, 197–202.
Lee, J. H. & Glass, I. I. 1982 UTIAS Rep. no. 262.
Mach, E. & Salcher, P. 1887 Akad. Wiss. Wien abt. II, 764–780.
Schneyer, G. P. 1975 Phys. Fluids 18, 1119–1124.
Schtultz-Grunow, F. 1975 Z. Flugwiss. 23, 51–57.
Shirouzu, M. & Glass, I. I. 1982 UTIAS Rep. no. 264.