Numerical simulation of vortex-induced vibration of a vertical riser in uniform and linearly sheared currents

Abstract

This paper presents a numerical study on vortex-induced vibration (VIV) of a vertical riser subject to uniform and linearly sheared currents. The model vertical riser tested at the MARINTEK by ExxonMobil is considered. The predicted numerical results are in good agreement with the experimental data. It is found that the dominant mode numbers, the maximum root mean square amplitudes, the dominant frequencies and the fatigue damage indices increase with the flow velocity. A standing wave response is observed for the single-mode in-line (IL) and cross-flow (CF) vibrations. Dual resonance is found to occur at most of the locations along the riser. At some locations along the riser, a third harmonic frequency component is observed in the CF response and a frequency component at the CF response frequency is found in the IL response apart from the frequency component at twice the CF response frequency. The majority of the vortex shedding shows a clear 2S pattern, whereas a 2P mode is observed near the position where the maximum vibration amplitude appears. The higher IL fatigue damage in the present study emphasises the importance of the IL fatigue damage especially in the design of low flow velocity or low mode number applications

The effect of cubic stiffness nonlinearity on the vortex-induced vibration of a circular cylinder at low Reynolds numbers

“…The initial conditions for the motion quantities of the cylinder are assigned as y = 0 andẏ = 0. Similar computational domain size and boundary conditions have been used in our previous numerical simulations of the VIV of rigid and flexible cylinders (Wang and Xiao, 2016;Wang et al, 2017).…”

Effect of Top Tension on Vortex-Induced Vibration of Deep-Sea Risers

“…The VIV response of TTR can be calculated numerically by finite difference method (FDM) according to Equations (1)- (6). The time history of VIV of TTR at each depth are obtained.…”

“…The prediction of VIV of a deep-sea riser was a challenging task since the incident current was practically non-uniform and the associated fluid-structure interaction (FSI) phenomena was highly complex. Wang and Xiao [6] presented an investigation on the VIV of the riser in uniform and linearly sheared current by means of a fully 3D FSI simulation. They pointed out that the dominating modes of the riser in uniform and linearly sheared current with the same surface velocity had no great difference.…”

2 – Way Fluid – Structure Interaction Study for the DIFIS System’s Riser Tube

“…The development of the computer's hardware and software was crucial for the realization of these analyses. The use of millions elements for mesh modeling in CFD models is observed in studies [7], [8], since the fluid domain around the riser tube is very large. In study [9], there is a comparison between computational results and experimental data and it is mentioned that there are possible optimizations due to the rapid development of computers' memory (RAM).…”