(Vortex Induced Vibration) VIV Suppressors Strakes
Tension Leg Platform (TLP) Risers suffer from Vortex-Induced Vibration Floatable and tension-leg platform risers suffer from vortex-induced vibration caused by strong currents.
Strong currents are challenge for deepwater drilling. As the search for oil and gas moves to deeper waters, drilling in strong currents becomes a serious problem, especially as operators increasingly are using floatable and tension leg platforms.
As current flows around unsupported pipe, such as pipeline risers, it creates vortices behind the pipe. When these vortices break away from the pipe, they set up vibrations which will dynamically excite the riser and cause the pipe to fail prematurely.
Strong currents increase the amount of vortex-induced vibration (VIV). Currents, such as the Loop Current which wreaked havoc in the Northern Gulf of Mexico in 1989, can so dynamically excite the riser that the riser has to be disconnected and pulled and driving suspended.
Minimizing vortex-induced vibration is no easy task.
The effect of vortex-induced vibration on not only the mooring system but also the riser system must be considered when designing a tension-leg platform.
In addition, various devices and configurations are attached to pipe surfaces t
o break up, or suppress, these vortex-causing currents. Options include:
- Alternating buoyant and bare joints of drilling riser in the high current area
- Placing fairings or strakes on the outside of the drilling riser