1. 1970 N2 2.5 0.3 0.75 Equilibrium 20 1973 N2 5 0.1 0.5 Equilibrium 22 1995 Air 15 0.028 0.42 Equilibrium 23 1989 N2 10 0.016 0.16 Nonequilibrium the fourth experiment23was about one-third or less of those in the first three. In Refs. 20, 22, and 23, the radiation measurement was made at several different lines of sight located at different distances away from the wall. The results for the third experiment are reproduced in Fig. 2.
2. In Fig. 4, the intensity ratios between the atomic nitrogen lines at 742- 747 nm and the first negative bands are N 2 shown as a function of enthalpy. As seen here, the intensity ratio is a strong function of enthalpy. A 10% error in the determination of intensity ratio results in only 2.5% error in enthalpy. A similar relationship exists between atomic nitrogen lines and NO bands. In the cases where enthalpy is too low for the nitrogen lines to emit significant radiation, the atomic oxygen line at 777 nm can be used instead, with a similar degree of accuracy. per line because it was the most prominent radiation feature; Bamford et al.12,24used an atomic oxygen line because a copper line was too weak to be reliable. The two results are compared in Figs. 6a and 6b.
3. Survey of measurements of flow properties in arcjets