PARAMETRIC ANALYSIS OF FLOW-INDUCED PULSATIONS ACOUSTIC PHENOMENA IN CORRUGATED PIPES

• Main Author: Putra Karsa, Labdawan
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/83048
• Institution: Institut Teknologi Bandung

In recent decades, there has been significant development in the use of flexible pipes in floating production facilities worldwide. Historically, several flexible pipes, particularly flexible risers, have experienced high-amplitude pressure fluctuations above critical velocities, leading to mechanical vibrations that can cause pipeline failures both topside and subsea. This issue can be identified by the presence of Flow-Induced Pulsations (FLIP) from the carcass of flexible pipes, which have an uneven profile. Within the pipe contour, an unsteady shear layer forms, which becomes the primary source of noise. This study's first objective is to investigate the fluid flow patterns through corrugated pipes and the effect of pipe geometry on the whistle amplitude and the Strouhal number of peak whistle amplitude. Additionally, the optimal characteristic dimensions for the Strouhal number are evaluated and proposed. This objective is achieved through numerical simulation using Computational Fluid Dynamics (CFD) software. The varied parameters include cavity depth, upstream edge radius, downstream edge radius, cavity width, and plateau length, relative to the associated sound amplitude and Strouhal number. It was found that the trend of sound amplitude changes can be observed from the variations in cavity depth, upstream and downstream edge radius. Meanwhile, the trend of Strouhal number changes is seen from variations in upstream edge radius, downstream edge radius, and cavity width. Furthermore, several optimal characteristic dimensions were evaluated. It was found that the ratio of the square of the plateau length to the sum of the cavity width and the upstream edge radius produces the optimal characteristic dimension for the Strouhal number in the case of corrugated pipes, as it shows the smallest variation in Strouhal number compared to other length ratios. This characteristic length enables more accurate and effective prediction of critical flow conditions for addressing whistling phenomena using the proposed equation. It also allows for the selection of pipe geometry configurations when flow conditions cannot be manipulated.