Measurement of acoustic wave phase velocity by Fourier method in gas-liquid medium

Results of measuring the phase velocity of weakly nonlinear waves in a gas-liquid mixture by the Fourier method are presented. The method is based on expansion of time signals, taken from two closely spaced pressure gages in propagation of a single finite pressure pulse, into Fourier series and calculation of the phase shift over the entire frequency series. The method was previously tested in a numerical experiment with the use of the known Korteweg–de Vries equation model. The results of phase velocity measurements show that the method is in good agreement with the theory in a frequency range where the phase incursion is under 2π. The proposed method makes it possible to reconstruct all parameters of polydisperse gas-liquid medium, including those of Landau attenuation analog, by the frequency dependence of the measured phase velocity.