The Impact of Turbulence on Hydroacoustic Waves
Traditional research suggests that when sound waves pass through a turbulent region, scattering occurs, causing the incident wave to attenuate and wave parameters to fluctuate. In contrast, our previous paper reported a new phenomenon in which turbulence causes changes in the amplitude of sound waves, a change that cannot be explained by scattering or resonance (HU, K.X, & HU, Y. J. 2025. Hydroacoustic Absorption and Amplification by Turbulence. arXiv:2512.07920). This work presents a more in-depth investigation into the impact of turbulence on hydroacoustic waves, including phase changes, amplification factors and the temporal evolution of the acoustic wave. Experiments indicate that turbulence simultaneously changes both the amplitude and phase of acoustic waves. The total phase shift along the entire pipe equals the sum of the phase shifts of the segments. Both the amplification factor and the phase shift due to turbulence vary periodically with frequency. In pipe flow, after the valve is closed, the temporal evolution of the acoustic waves during the subsequent turbulence decay process can be classified into six types. Acoustic waves with frequencies below and above specific thresholds are essentially unaffected by turbulence. In addition, vortices and unsteady flow in the laminar state do not cause changes in the amplitude and phase of sound waves, showing the essential difference between turbulent fluctuations and the two.