VIV @ FlexNARA

Vortices

Vortices generated when flows past cylinder

VIV of flexible cylindrical structures such as marine risers, subsea pipelines, cables, mooring lines & tethers exhibits several interesting fluid-solid interaction phenomena (e.g. dual resonances, hysteresis, higher harmonics, mode switching, mode sharing, travelling wave, drag amplification). When exposed to sea current flows, these slender bodies undergo nonlinear large-amplitude oscillation due to the space-time varying hydrodynamics associated with vortex shedding. Because VIV results in an increased mean drag and high oscillating stress-induced fatigue in long flexible structures, VIV is one of the utmost concerns in deepwater developments.

In the past decade, FlexNARA has been developing computationally efficient models and analysis tools which have been used to examine a variety of VIV phenomena associated with combined hydrodynamics and structural geometric nonlinearities, see our publications. We have developed an experimental framework as below and combined analytical-numerical approaches to deal with several VIV problems.