Numerical investigation on VIV suppression of marine riser with triangle groove strips attached on its surface

The effects of Triangle Groove Strips (TGS)on Vortex-induced Vibration (VIV)suppression of marine riser are numerically investigated using Computational Fluid Dynamics (CFD)method. The range of Reynolds number in simulations is 4.0 × 10⁴ < Re < 1.2 × 10⁵. The two-dimensional unsteady Reynolds-Averaged Navier-Stokes (RANS)equations and Shear Stress Transport (SST)k-ω turbulence model are used to calculate the flow around marine riser. The Newmark-β method is employed for evaluating the structure dynamics of marine riser. The effect of the height ratio (ε)of TGS on VIV suppression is evaluated. The amplitude responses, frequency responses, vortex patterns and the flow around the structures are discussed in detail. With the increase of the height ratio of TGS, the suppression effect of TGS on VIV suppression is improved firstly and then weakened. When ε = 0.04, the suppression effect of TGS is the best. Compared with the VIV responses of smooth marine riser, the amplitude ratio is reduced by 38.9%, the peak of the lift coefficient is reduced by 69% and the peak of the drag coefficient is reduced by 40% when Re = 6.0 × 10⁴. With the increase of Reynolds number, the suppression effect of TGS on VIV suppression is improved firstly and then weakened. When the Reynolds number is 7.0 × 10⁴, the amplitude ratio can be reduced by 40.1%. As to the large-amplitude vibration cases, the TGS show nice suppression effect on VIV.