R. Yano et al., Supersonic nonequilibrium plasma wind-tunnel measurements of shock modification and flow visualization, AIAA J, 38(10), 2000, pp. 1879-1888
Experiments conducted in a new, small-scale, nonequilibrium plasma wind tun
nel recently developed at Ohio State University are discussed. The facility
provides a steady-state supersonic flow of cold nonequilibrium plasma with
well-characterized, near uniform, properties. The plasma is produced in ae
rodynamically stabilized high-pressure glow discharge that forms the plenum
of the supersonic nozzle, The possible modification of the supersonic flow
due to ionization is studied by measuring the angle of oblique shocks atta
ched to the wedge located in the nozzle test section. The results do not sh
ow any detectable shock weakening or attenuation in weakly ionized nitrogen
plasma, compared to the measurements in a nonionized gas flow. Experiments
in supersonic flowing nitrogen and helium afterglow also demonstrate a nov
el technique for high-density supersonic Row visualization. It allows ident
ifying all key features of the supersonic Row, including shocks, boundary l
ayers, flow separation regions, and wakes by recording intense visible radi
ation of the weakly ionized plasmas. Interpretation of radiation intensity
distributions in nonequilibrium supersonic Rowing afterglow may provide inf
ormation on key mechanisms of energy storage and ultraviolet radiation in h
igh-altitude rocket plumes. In addition, these flow visualization experimen
ts can be used for validation of multidimensional computer flow codes used
for internal Row simulation.