On the delicate state of instability of a vertical riser transporting fluid
- Author(s): Kim, HT
- O'Reilly, OM
- et al.
Published Web Locationhttps://doi.org/10.1016/j.jfluidstructs.2019.102811
© 2019 Elsevier Ltd The variation in the dynamic characteristics of a flexible riser as the riser transitions from a vertical riser to a catenary-type riser is investigated. It is well known that the straight configuration of a flexible vertical riser conveying fluid destablizes in a divergence-type instability once the velocity of the transporting fluid exceeds a critical speed. As expected, the instability persists if a slight horizontal offset is introduced at the hang-off point. However, as demonstrated in this paper, if a finite horizontal offset is introduced then the instability vanishes and the resulting static configuration of the catenary-type riser is stable regardless of the transport speed of the fluid.