A numerical study on the installation configuration design of steep wave riser (SWR) in deep water

A new calculation procedure is presented for the structural analysis of a steep wave riser (SWR) system. The equilibrium equation of the SWR is established based on Minimum total potential energy principle. The coupled equations are discretized by the finite difference method and then solved by Newton-Raphson technique. The accuracy of the numerical model is verified by Orcaflex software. Traditional parametric analysis of buoyancy factor, buoyancy section's length, buoyancy section's location and ocean current velocity are performed. An idea of engineering evaluation of the SWR's working condition from the perspective of hang-off angle, tension, and bending radius is proposed. Through comparison, it is found that the hang-off angle is the main parameter affecting the installation safety of the SWR. And the allowable working water depth and installation span are determined. In addition, the optimization idea of the SWR's configuration based on S-shape coefficient and hang-off angle is put forward, and the optimal configuration of a specific SWR is analyzed.