Sound and Ultrasound Absorption Resulting from Heat Radiation

Following a suggestion by Markham, Beyer, and Lindsay, the Stefan-Boltzmann radiation law is applied to estimate the attenuation of approximately plane compression waves resulting from heat radiation. The attenuation is found to be independent of the frequency of the compression waves in the entire relevant frequency range and inversely proportional to a linear dimension of the wave fronts. At ordinary temperatures, this attenuation is negligible compared to that due to thermal conduction and viscosity, verifying the results of Rocard and Rayleigh. In gases at temperatures of 1000°K or more, however, the attenuation due to heat radiation is not entirely negligible under certain conditions.