A coupled numerical approach for nonlinear dynamic fluid-structure interaction analysis of a near-bed submarine pipeline

摘要

Purpose - The purpose of this paper is to develop an effective numerical approach to assess the nonlinear dynamic responses of a near-bed submarine pipeline. Design/methodology/approach - A coupled numerical approach is proposed in this paper to assess the nonlinear dynamic responses of this pipeline. The boundary-element method is first used to get the nonlinear dynamic fluid loading induced by the asymmetric flow. The meshless technique is used to discretize the structure of the pipeline. A numerical example is first presented to verify the effectivity of the present method. Then, the coupled technique is used to simulate the nonlinear dynamic fluid-structure interaction problem of a near-bed pipeline. A Newton-Raphson iteration procedure is used herein to solve the nonlinear system of equations, and the Newmark method is adopted for the time integration. Findings - The presence of seabed results in a large negative lift on a pipeline in a horizontal current. Studies reveal that there exists a critical current velocity, above which the pipeline will become instable, and the critical velocity is significantly affected by the initial gap from the pipeline to the seabed. Originality/value - The near-bed submarine pipeline is a widely used structure in marine engineering. This paper originally develops a numerical approach to model this special fluid-structure interaction problem. It has demonstrated by the examples that the present approach is very effective and has good potential in the practical applications.