A concentration probe for the study of mixing in supersonic shear flows

An aspirating hot-film probe is developed to measure local mean gas composition in supersonic flows. The probe consists of a constant temperature hot-film sensor operating in a channel with a choked exit. Thus, the flow over the hot film is influenced only by total temperature, total pressure, and gas concentration. The use of the probe requires a separate measurement of the total temperature in the gas flow. The probe has a spatial resolution of 0.011 in. and shows acceptable sensitivity to flow angularity. The probe is used in the study of an unheated supersonic air/helium mixing layer in a 23 cm × 23 cm supersonic wind tunnel. Data are presented in raw form and after reduction to concentration and mean flow quantities.