Experimental investigation on characteristics of flow-induced acoustics in horizontal gas–liquid two-phase flow

The dynamic behavior of bubbles and their interactions with fluid walls in bubble-laden liquid flows inevitably generate outwardly propagating sound waves, which are crucial for monitoring pipeline stability. However, the influence of flow patterns on gas–liquid two-phase flow-induced sound (GTFIS) emissions, especially under high Reynolds numbers, remains inadequately understood. In this study, GTFIS signals under high Reynolds numbers in a horizontal pipe were captured using a precision hydrophone. The results reveal that the energy of GTFIS signals is predominantly concentrated within 0–50 Hz. Among all flow patterns in conventional horizontal pipes, slug flow (SG) exhibits the highest GTFIS signal intensity. The signal intensity in SG increases linearly with gas velocity due to the combined effects of rising bubble-induced turbulence effect and slug frequency. In intermittent flow, the GTFIS signal exhibits increased non-Gaussianity and approximately follows a stable distribution. The structural complexity and multifractality of GTFIS signals are governed by bubble behavior and flow pattern transitions. Furthermore, in intermittent flow, the multifractal strength is maximized due to the enhanced intermittency of the internal flow and the inhomogeneous two-phase distribution. The parameters of the multifractal spectrum for GTFIS emerge as effective tools for flow pattern classification.