Theory and model tests for the dynamic response of free hanging risers

✍ Scribed by M.H. Patel; A.S. Jesudasen

• Publisher: Elsevier Science
• Year: 1987
• Tongue: English
• Weight: 994 KB
• Volume: 112
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1016/s0022-460x(87)80099-8

✦ Synopsis

A theoretical and experimental investigation is presented of the lateral dynamics of free hanging marine risers. In offshore oil exploration and production activities such long vertical steel riser pipes are used as conduits connecting a floating surface vessel to a subsea well head. During riser retrieval or in storm conditions, the riser is disconnected from the subsea well head and remains hanging freely from the surface vessel while being subjected to excitation by surface vessel motions, waves and current. The riser responds by displacements and stresses both in and out of the plane of excitation due to direct loading and vortex shedding effects respectively. The in-plane behaviour has been investigated through a finite element analysis of the riser pipe and its hydrodynamic loading. Results of this analysis are compared with model test data at 1 : 28 scale from a specially designed deep water tank. Some measurements of the out-of-plane behaviour of the riser due to vortex shedding effects are also presented.