Numerical Analysis of Hydrodynamics Around Submarine Pipeline End Manifold (PLEM) Under Tsunami-Like Wave

Abstract

Submarine Pipeline End Manifold (PLEM) is the converge end or termination of submarine pipelines, which is used to provide additional support for equipment in the submarine production system on the seafloor. However, PLEM is vulnerable to extreme waves (i.e., tsunami waves). In this study, a two-phase flow model is developed with the finite volume method for simulating the tsunami-like wave impinging on the PLEM. Depending on the real-world tsunami wave recorded in 2011 tsunami event, a tsunami-like wave is generated numerically depending on N-waves theory. In order to ensure the accuracy of the calculation, this model is verified against some theoretical and experimental studies firstly. Then, the hydrodynamic characteristics and forces on the PLEMs under the different tsunami-like waves are investigated systematically. Due to the flow causes strong disturbance to different parts of the PLEMs, the Fast Fourier Transform (FFT) method is adopted to analyze the irregular hydrodynamic force signals for better to understand the characteristics of forces in the frequency domain. In the simulations, different environmental and PLEM structural variables are considered, such as wave height, pipe distance, and PLEM bottom seat length. The hydrodynamic characteristics under different tsunami-like waves passing the various submarine PLEMs are discussed, which indicates that the vortex field evolutions and hydrodynamic forces under different waves on the PLEM are significantly different.

Keywords

• Tsunami-like wave
• submarine pipeline end manifold (PLEM)
• hydrodynamic forces
• flow field
• vortex