Flow-Induced Vibration Analysis of Rigid Horizontal Pipelines Under Two-Phase Flow and Leak Conditions

This study investigates the vibrational response of horizontal rigid pipelines subjected to internal two-phase flow with simulated leaks. Using spectral-based contour plots and vibrational energy measurements, we analyze the dynamics across various flow velocities and patterns in a 5-m-long, 2-in diameter pipeline. Results indicate that flow patterns and Reynolds numbers significantly influence vibration characteristics. Except for bubbly flow, increasing the mixture Reynolds number amplifies power spectral magnitudes and extends excitation to higher frequencies, independent of leaks. Fluid loss enhances spectral magnitudes at higher liquid Reynolds numbers, with gas Reynolds numbers further intensifying vibration. Leaks modify spectral spikes due to multiphase flow fluctuations, making them more pronounced and persistent. Vibrational augmentation is predominant in the direction of fluid loss, peaking at the leak location and attenuating with increasing distance from the leak location. Slug flow demonstrates the highest increase in vibrational energy. Bubbly flow exhibits maximum leak to no-leak amplification (15–25 dB), followed by slug flow (5–15 dB), and plug flow (<10 dB). Minimal leak-induced effects (<5 dB) occur in stratified wavy and low-velocity intermittent flows. This study establishes a foundation for leak detection and pipeline health monitoring, emphasizing the role of flow-induced vibration analysis in enhancing pipeline safety.