Numerical and experimental investigation of the flow and scour around subsea structures

Abstract

The uncertainty inherent in predicting scour depths at subsea structures in offshore oil and gas engineering such as subsea caissons, gravity anchors and wind turbines is currently a significant barrier to achieving an optimal and cost-effective foundation design. Therefore, securing subsea structure is a major concern for the oil and gas industry and environmental advocates. Few approaches are described in the literature to estimate local scour and flow structure at various spacings across the cylinder and variation in flow directions. In this thesis, comprehensive research on local scour around subsea structures was conducted using 3D numerical simulations and experiments in a water flume to understand the fundamental mechanism of flow and scour. Non-dimensional 3D NS equations for incompressible flow were solved by the Petrov–Galerkin FEM. The SST k–ω equation was also used in the numerical models to simulate local scour around subsea structures. Moreover, experiments were conducted to observe local scour around submerged short, square piles and unburied pipeline sleeper system models. The effects of different flow directions and angles of arrangement of the models were investigated under clear-water scour conditions.

Date of Award	2023
Original language	English
Awarding Institution	Western Sydney University
Supervisor	Ming Zhao (Supervisor)