VIV Response Prediction for Long Risers With Variable Damping

This paper describes the Vortex Induced Vibration (VIV) response of long cylinders equipped with strakes and present damping measurements from Gulf Stream Experiments conducted in October 2006. The experiments used a 500.4 foot (152.4 m) long composite pipe with an outside diameter of 1.43 inches (3.63 cm). The strakes were a triple helix design with a pitch to diameter ratio of 17.5. The pipe was equipped with varying amounts of strake coverage and was towed in the Gulf Stream which had current profiles which varied from nearly uniform to highly sheared. The measured response showed the characteristic of traveling waves. Modeling such response using mode superposition and Green’s Function is presented.