The Effect of Mooring System and Sheared Currents on Vortex Induced Motions of Truss Spars

Dijk, Radboud R. T. van; Voogt, Arjan; Fourchy, Paul; Mirza, Saadat

doi:10.1115/omae2003-37151

Cited by 13 publications

(4 citation statements)

References 2 publications

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“…This influence is directly related to the position of the appendages, fairleads and chains on the hull. van Dijk et al (2003) and Irani and Finn (2004) reported that waves have also effect on VIM of a spar. In the same sense, Finnigan et al (2005) presented the first results regarding truss spar VIM in the simultaneous presence of waves and current, which showed that waves in-line with the current direction generally reduce VIM response.…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical studies of the pontoon effect on vortex-induced motions of deep-draft semi-submersibles

Liu

Xiao

Liang

et al. 2017

Journal of Fluids and Structures

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The vortex-induced motion (VIM) is a critical issue in mooring and riser system design for column-type deepwater platforms. As regards to deep-draft semi-submersibles (DDS), even though VIM is mainly excited by vortex shedding around columns, the large-volume pontoons beneath the columns are also responsible for the wake interference, implying a non-negligible influence on VIM behavior. An experimental study and three-dimensional numerical simulations were performed to analyze the pontoon effect on the VIM of two semi-submersibles and a four-column structure without pontoons. The numerical results using Detached Eddy Simulation (DES) are in good agreement with the experimental measurements obtained from the towing model tests. The present investigations indicate that the resonant phenomenon is observed for all configurations. However, the four-column structure without pontoons shows the most significant transverse responses and yaw motions at both 0°- and 45°-incidences owing to the largest fluctuating lift forces induced by the well-established wake. Additionally, the negative values of work done by the pontoons at all reduced velocities confirm their damping effect on the VIM response

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Section: Introductionmentioning

confidence: 99%

Experimental and numerical studies of the pontoon effect on vortex-induced motions of deep-draft semi-submersibles

Liu

Xiao

Liang

et al. 2017

Journal of Fluids and Structures

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“…Numerical and experimental studies have been carried out widely on VIMs of cylinders and monocolumn platforms [1,2]. Gonçalves et al investigated the vortex-induced vibration of circular cylinders with very low aspect ratio and small mass ratio [3].…”

Section: Introductionmentioning

confidence: 99%

CFD Simulation of Vortex Induced Motion of a Caisson during Installation Process

Chen

Liu

2023

J. Phys.: Conf. Ser.

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This paper presents the CFD investigation of the vortex induced motion (VIM) of a caisson model during the installation process. The simulations were performed by solving the unsteady 3D Navier-Stokes equation. The Dynamic Fluid-Body Interaction (DFBI) tool is utilized to simulate the motions. Typical draft conditions of a caisson during installation process are considered. The present methodology is verified through the free decay and the VIM of a cylinder simulations in two-dimension. Free decay simulations show that the natural frequency decrease with the increasing draft of the caisson. Maximum response amplitudes occur in the range of 10<Vr <13 for the draft Dp=0.1m. The resonance occurs when the crossflow response frequency f y is very close to the natural frequency f n. The inline/crossflow response frequency increases as the draft increases at the same reduced velocity V r. The response frequency in the inline direction is double of that in the crossflow direction. Eight-shaped trajectories are observed. The maximum displacements in the crossflow direction increase as the drafts increase.

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“…The reliability of predicting full-scale VIMs through model testing was verified. Van Dijk et al 21 further conducted a model test comparing the VIM responses under various simulation methods of incoming current. One method was implemented by dragging the model in calm water, and the other was implemented by generating a current in the basin, respectively.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the VIMs of a spar-type FOWT using a model test method

Duan

Wang

2016

Journal of Renewable and Sustainable Energy

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This article presents the research findings of an extensive model test investigation of the dynamic response to vortex-induced motions (VIMs) of the OC3 spar-type floating offshore wind turbine (FOWT). Particulars of this research are to investigate the unique and crucial effects of wind load on the spar-type FOWT, which differs considerably from other traditional spar-type floating systems utilized in the gas and oil industry, on the VIMs. The model test was performed with a sequence of current, wind and irregular wave sea states to analyze the nature of the coupled dynamic response behavior of VIMs. Many unique characteristics were found and analyzed. The lock-in phenomenon of sway in the cross flow (CF) direction was found to occur first, followed by the lock-in phenomenon of surge in the in-line (IL) direction. For the current-only case, the remaining responses, including the other 4-degree-of-freedom (DOF) motions, mooring tensions and turbine bearing loads, were found to be coupled by sway/surge VIMs. Moreover, the oscillation amplitudes of all of the responses increased significantly with increasing current velocity, particularly after locking-in. Furthermore, the wind load had a clear suppression effect on the CF and IL VIM responses. The experimental measurements demonstrated that the wave load excites wave-induced oscillations for some CF responses and all IL responses, and it further restrains the VIM oscillation amplitudes on the foundation of the wind suppression effect. In particular, when a wind load is involved, the influence of current or wave is limited to the yaw and IL tower-top bending moment.

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The Effect of Mooring System and Sheared Currents on Vortex Induced Motions of Truss Spars

Cited by 13 publications

References 2 publications

Experimental and numerical studies of the pontoon effect on vortex-induced motions of deep-draft semi-submersibles

Experimental and numerical studies of the pontoon effect on vortex-induced motions of deep-draft semi-submersibles

CFD Simulation of Vortex Induced Motion of a Caisson during Installation Process

Investigation of the VIMs of a spar-type FOWT using a model test method

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