Measurement of times of vibrational relaxation and dissociation behind shock waves in N 2, O 2, air, CO, CO 2 and H 2

Abstract

A modified sodium-line reversal method is used to measure the temperature behind shock waves and to study its variation with time. The reversal temperature follows the effective vibrational temperature of the gas molecules. In N2, CO and air the temperature is initially too low because of vibrational energy lag; for oxygen the vibrational lag is very short, but temperatures are too high because of delay in dissociation. CO2 shows a short but measurable vibrational lag, attributed to the asymmetrical vibration, v3, and a longer dissociation lag. Hydrogen-argon mixtures also show effects attributed to both vibrational and dissociation delays. Results are tabulated.