Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Numerical Analysis of Vortex-Induced Vibration Suppression of a Flexible Riser Attaching with
Symmetric Strips
Hao Hu1, Zhiyuan Wei2, Decheng Wan1*
1Computational Marine Hydrodynamic Lab (CMHL), School of Naval Architecture, Ocean and Civil Engineering,

2Shanghai Jiao Tong University, Shanghai, China
Marine Design and Research Institute of China, Shanghai, China*Corresponding author

passive control devices. Thus, the researches on the passive control
methods are introduced in the following subsection.

ABSTRACT
A computational fluid dynamics (CFD) model is built to analyze theVortex-Induced Vibration (VIV) Suppression of a flexible riser
attaching with symmetric strips suffering to the uniform current. The
thick strip model and the Navier-Stokes method are applied to solve theflow field, the Bernoulli–Euler bending beam model and Finite Element
Method (FEM) are employed to obtain the vibration displacements ofriser. During numerical calculations, the symmetric strips are arranged
at 45 degree on the surface of riser to the flow direction with a constantwidth of 0.2D and three varying thicknesses of 0.03D, 0.05D and 0.08D.
The dimensionless Root Mean Square (RMS) displacements, modalweights, vibration frequencies, and the wake flow field are compared.
The results indicate that this configuration has fine ability to suppress
VIV especially at the symmetric strips thickness of 0.08D.

Huera-Huarte (2017) tested the VIV of the cylinder with different
densities and sizes wire meshes, they concluded that this device canaffect the boundary layer and suppress the vortex street, meanwhile, thedrag coefficient had no increased in most cases. Ren et al (2019)
experimentally investigated the VIV suppression effect of the flexible
riser with different Keulegan-Carpenter (KC) numbers and maximum
reduced velocities in oscillatory flow, the analysis results indicated thatthe suppression efficiency in oscillatory flow was limited at low KC
numbers and reduced velocities compared to uniform flow. Li et al(2020) conducted an experiment to verify the VIV suppression effect of
the flexible cylinder installing with the bird-wing-shaped device, theresults showed that the velocity of flow field was reduced, and the VIV
suppression effect was related to the length of device. Li et al (2020)
experimentally studied the VIV responses of the discrete helical strake
flexible riser with different start helical strakes and discrete spacings,
and they found that the three-starts discrete helical strakes showed thebest suppression effect regardless of different discrete spacings.

KEY WORDS: VIV suppression; uniform current; symmetric strips;
viv3D-FOAM-SJTU solver;

INTRODUCTION

Law and Jaiman (2018) modified the rigid cylinder with staggered andhelical grooves, the numerical simulations showed that the rigidcylinder with staggered grooves showed more high suppression
efficiency, where the inline and crossflow amplitudes were reduced to
37% and 75% respectively. Zhu (2020) developed two-dimensional
numerical model with direct numerical simulation (DNS) to investigate
the VIV suppression efficiency of a cylinder with splitter plates locatedupstream and downstream, this arrangement can effectively suppress
VIV at certain reduced velocity, and the suppression efficiency wasimproved with the longer plate. Ishihara and Li (2020) constructed theCFD model through Large eddy simulation (LES) turbulence method tosimulate the VIV responses of the rigid cylinder with helical wires, it
was found in the numerical results that the lift coefficient was

The positive and negative vortices are released in the wake region ofthe marine riser when it suffers to current. The generation andmigration of these vortices bring a typical fluid-structure interaction
phenomenon called VIV. Due to the large aspect ratio of the marineriser, the huge deflection of the marine riser caused by VIV contributes
to the fatigue damage, which results in the leakage of internal gas andoil. Therefore, to ensure the stability of the marine riser, the VIVcontrol strategies have been researched by many scholars in the pastdecades.
Hong and Shah (2018) had reviewed the recent investigations on thepassive and active control strategies of VIV. Considering maintenanceand economical costs, the marine riser is commonly equipped with the2549