Model and collision prevention control for 2-D vessel-riser array system based on improved wake interference model

In marine oil production engineering, the collision of risers will produce negative impacts on production and marine environment, which is an urgent issue to be addressed. Considering the slender characteristics of flexible risers, this paper introduces the longitudinal axis and root mean square to improve the applicability of the Blevins wake model. Based on this, a two-dimensional vessel-riser array mathematical model is established considering the lift of the flow field. The time domain and frequency domain vibration analysis and collision analysis of the riser array are carried out considering various riser arrangement modes. It was found that increasing the spacing and top tension cannot effectively prevent collisions in the system. Moreover, in the case of cross arrangement, the system collisions are more frequent. Based on the above work, a group of boundary controllers is designed to achieve the control purpose considering the control overflow. Finally, through numerical simulation, it is verified that the controller set can effectively avoid system collisions, the vibration amplitude is reduced, and the motion spacing is significantly increased. The feasibility and effectiveness of the controller set are verified.