SPECTRUM-LINE-REVERSAL TEMPERATURE MEASUREMENTS THROUGH UNSTEADY RAREFACTION WAVES IN VIBRATIONALLY-RELAXING OXYGEN
ROYAL AIRCRAFT ESTABLISHMENT FARNBOROUGH (UNITED KINGDOM)
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Pressure and spectrum-line-reversal temperature measurements were made of the structure of an unsteady expansion wave initiated in a vibrationally-excited gas in a shock tube by the rupture of a second diaphragm. With oxygen initially at about 2500 deg K and 0.75 atmospheres pressure the vibrational temperature was observed to fall from its initial fully-frozen value at the tail of the wave to a minimum before rising again to the original equilibrium value at the head of the wave. This agrees broadly with Appletons calculations based on a linear rate law and Landau-Teller theory for Tau sub v, although the temperature minimum was slightly higher and occurred later than he predicted it was also predicted qualitatively by Stulov. More detailed studies with, for example, nitrogen would be desirable for seeking a full explanation of the small differences with theory revealed by these preliminary tests.
- Atomic and Molecular Physics and Spectroscopy