Acoustic temperature measurement in a rocket noise field

A one-micron diameter platinum wire resistance thermometer has been used to measure temperature fluctuations generated during a static GEM-60 rocket motor test. Exact and small-signal relationships between acoustic pressure and acoustic temperature are derived in order to compare the temperature probe output with that of a 3.18 mm diameter condenser microphone. After preliminary laboratory testing yielded good agreement between the transducers within the temperature probe's $\sim $2-kHz bandwidth, comparison between the temperature probe and microphone data during the motor firing show that the $\pm \sim $3 K acoustic temperature fluctuations are a significant contributor to the total temperature variations.