Optical measurement of the speed of sound in air over the temperature range 300-650 K

Using laser-induced thermal acoustics (LITA), the speed of sound in room ai r (1 atm) is measured over the temperature range 300-650 K. Since the LITA apparatus maintains a fixed sound wavelength as temperature is varied, this temperature range simultaneously corresponds to a sound frequency range of 10-15 MHz. The data are compared to a published model and typically agree within 0.1%-0.4% at each of 21 temperatures. (C) 2000 Acoustical Society of America, [S0001-4966(oo)02910-6].