Acoustically generated temperature gradients in plates

Abstract

The results of measurements of thermoacoustically generated temperature gradients in short thin plates located in a resonant tube are reported. The temperature gradient, resulting from a heat flow generated by the acoustic field, is a function of the acoustic pressure amplitude, the Prandtl number of the gas, the configuration of the plates, and the position of the plates in the tube, Measurements were made for pressure amplitudes ranging from approximately 145–162 dB re: 20 μPa, in argon and helium, for single plates and stacks of up to five plates having separations from approximately 4 to 40 thermal penetration depths, and at various positions in the tube. The results are compared to predictions based on a theory by Wheatley and others [J. Wheatley et al., J. Acoust. Soc. Am. 74, 153–170 (1983)]. For pressure amplitudes below 150 dB, the measurements agree well with theory. At higher pressure amplitudes, the agreement diminishes, indicating the presence of effects not addressed by theory. [Work supported by NPS Foundation.]