The Temperature-Jump Effect and the Theory of the Thermal Boundary Layer for a Spherical Resonator. Speeds of Sound in Argon at 273.16K

The theory of the thermal boundary layer at the walls of a spherical acoustic resonator is discussed in detail. For gases at low pressures, the temperature-jump effect is found to make a significant contribution to the resonance frequencies of the radial modes but not to their acoustic losses. Experimental results are reported for argon at 273.16 K and pressures between 15 and 248 kPa, and compared with the theory. These were obtained using the four radial modes with lowest frequency of a spherical resonator with a radius of 60 mm. The thermal accommodation coefficient between argon and the aluminium wall of the resonator was found to be (0.84 ± 0.05). The results suggest that a determination of the gas constant with a fractional imprecision of 1 × 10-5 or better should be possible using a spherical acoustic resonator.