An Assessment of Recent Results on Pseudo-Stationary Oblique-Shock-Wave Reflections.
TORONTO UNIV DOWNSVIEW (ONTARIO) INST FOR AEROSPACE STUDIES
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The assumptions and criteria used in existing analyses in determining the regions and transition lines of pseudo-stationary oblique-shock-wave reflections were re-examined in order to improve the agreement between experiments and computed data for regular RR, single-Mach SMR, complex-Mach CMR and double-Mach reflection DMR. It is shown that the relaxation lengths for vibration and dissociation determine whether frozen or equilibrium gas transition lines are applicable. The available experimental data in N2, CO2 and air, which are based on the criterion consistent with relaxation lengths of the angle delta, between the incident and reflected shock wave, do not conclusively support the frozen or equilibrium gas calculations for N2 and air. It does support C02 as an equilibrium gas contrary to a previous conclusion of agreement with gamma 1.29. A new additional and necessary criterion for the transition from single to complex Mach reflection improves the agreement between analysis and experiment and is consistent with the requirements of the relaxation length and the angle delta. However, it now appears that a more accurate criterion is required for the boundary line between CMR and DMR. More detailed examination of the boundary-layer-displacement slope at the point of regular reflection appears to eliminate the von Neumann paradox and explains the persistence of regular reflection below the transition line for the occurrence of Mach reflection.
- Fluid Mechanics