We measured the resonance spectrum of an acoustic resonator filled with xenon near its critical temperature Tc. We reduced the effect of gravity on the xenon by convective stirring to achieve a temperature resolution of (T-Tc)/Tc 7 10-6. The data yield accurate values of xenon s speed of sound, acoustic dissipation, and thermal conductivity. Linear acoustics, including the frequency-dependent bulk viscosity from renormalization-group theory, predicts the dissipation within the thermoacoustic boundary layer peaks at characteristic temperatures. The peak was not observed. We show that critical-point adsorption is one mechanism that can suppress the peak.
Citation: Physical Review Letters
Pub Type: Journals
acoustic resonators, adsorption, attenuation, bulk viscosity, convection, critical point, speed of sound, thermoacoustic boundary layer, ultrasonics xenon