Abstract: Pipe vibration induced by cavitating flow in a pipe system is an important factor that damages the pipe system. This paper focuses on the interaction between flow disturbance and cavitation, as well as its impact on pipeline vibration. Zwart-GerberBelamri (ZGB) cavitation model is used to study the dynamic evolution of the cavitation cloud with the cavitation number and Reynolds number under the influence of small perturbations. The cavitation cloud is found to cause an unbalanced force and flow pulsation in the pipeline. Furthermore, the cavitation cloud has amplitude modulation and frequency conversion characteristics, which aggravate the amplitude and change the frequency of the unbalanced force and flow pulsation. Based on this, an excitation source term, cavitation excitation, is introduced into the fluid structure coupling dynamic model, and an improved fluid structure coupling dynamic model for analyzing the mechanism of pipeline vibration induced by cavitation is established. The equations for the vibration of a pipeline under cavitation excitation are solved, and the critical cavitation number interval is determined. Moreover, the causes of pipeline vibrations induced by cavitation under small perturbations are revealed. The results are essential for studying vibration and noise reduction and the safe operation of pipeline systems.

Key words: cavitation, fluid structure coupling model, amplitude modulation and frequency conversion, infusion pipeline, vibration