Numerical simulation study on the mechanism of acoustic wave propagation in gas-liquid two-phase stratified flow

Pipeline acoustic leak detection in gas-liquid flows is hindered by unclear wave propagation and attenuation. Using a VOF multiphase flow model and real gas equation of state, this study simulates sound waves in stationary gas-liquid stratified flow. It validates the plane wave assumption, quantifies pressure/velocity perturbations in both phases, and investigates high pressure and frequency effects. Results reproduce experimental sound speed trends and confirm that within a wavefront, pressure perturbations are consistent across phases while velocity perturbations differ significantly. An improved sound speed model is developed using thermodynamic correction and real gas effects under high pressure. Acoustic attenuation characteristics are systematically quantified, revealing that attenuation is strongly influenced by velocity shear at gas-liquid interfaces and viscous dissipation effects. An engineering estimation equation for the attenuation coefficient is established, accounting for pressure, frequency, and amplitude. This provides a theoretical reference for high-precision acoustic leak detection in multiphase pipelines.