scholarly journals Dynamic response of the mooring system in the floating photovoltaic power station

2021 ◽  
Vol 2087 (1) ◽  
pp. 012028
Author(s):  
Fei Yu ◽  
Yi Su ◽  
Yuliang Liu ◽  
Haibo Liu ◽  
Fei Duan
Keyword(s):  
Numerical Model ◽  
Dynamic Response ◽  
Potential Theory ◽  
Carbon Emission ◽  
Three Dimensional ◽  
Mooring System ◽  
Power Station ◽  
Mooring Lines ◽  
Environmental Loads ◽  
Photovoltaic Power

Abstract The floating photovoltaic power (FPV) station becomes popular to decrease carbon emission. However, limited research has been done on the dynamic response of the mooring lines of the FPV array. Based on a typical 2.14MW FPV array, this study investigates the displacement of the array and the mooring tension of the mooring lines. The numerical model of the FPV array is built through three-dimensional potential theory with 124 mooring lines. Firstly, the effect of the environment on the response is investigated under wave-only, current-only and wind-only conditions. Then, the tension and motion in the combined environmental loads are analyzed. It is found that the wind load has the greatest influence on the motion and mooring tension on the FPV power station, the effect of wave and current on the response is very limited.

An Innovative Synthetic Mooring Solution for an Octagonal FPSO in Shallow Waters

2010 ◽  
Author(s):  
Mo Fan ◽  
Da Li ◽  
Tuanjie Liu ◽  
Alex Ran ◽  
Wei Ye
Keyword(s):  
Oil And Gas ◽  
Shallow Waters ◽  
Manufacturing Processes ◽  
Mooring System ◽  
Oil And Gas Development ◽  
Mooring Lines ◽  
Environmental Loads ◽  
Design And Manufacturing ◽  
Full Production ◽  
Three Bundles

An octagonal FPSO has been proposed for marginal oil and gas development in shallow waters. A shuttle tanker will be deployed near the FPSO during offloading operations. This new concept simplifies the design and manufacturing processes, yet maintains full production, storage, and offloading functions of a conventional ship-shaped FPSO. However, design of the mooring system for this floating unit imposes technical challenges due to: 1) high environmental loads expected on this unit, 2) large dynamic offsets of the unit in shallow waters, and 3) inadequate performance of catenary mooring systems in shallow waters. Thus, development of a viable station keeping solution becomes a key issue to the new concept FPSO design. In this paper, an innovative mooring system is designed to meet the challenges. The FPSO mooring system consists of pile anchors, bridle chains, anchorage buoys, and polyester ropes. Nine mooring lines are grouped into three bundles which evenly spread around the FPSO. The shuttle tanker is attached to the FPSO with a nylon rope hawser at the bow and secured to pre-installed anchorage buoys at the stern with two other nylon ropes. Analyses have been performed for the FPSO mooring system. It is concluded that the proposed mooring system is fully functional and effective.

scholarly journals Dynamic Response for a Submerged Floating Offshore Wind Turbine with Different Mooring Configurations

2019 ◽  
Vol 7 (4) ◽  
pp. 115 ◽  
Author(s):  
Yane Li ◽  
Conghuan Le ◽  
Hongyan Ding ◽  
Puyang Zhang ◽  
Jian Zhang
Keyword(s):  
Dynamic Response ◽  
Wind Turbine ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Mooring Line ◽  
Offshore Wind Turbine ◽  
Intermediate Water ◽  
Mooring System ◽  
Mooring Lines ◽  
Floating Offshore Wind Turbine

The paper discusses the effects of mooring configurations on the dynamic response of a submerged floating offshore wind turbine (SFOWT) for intermediate water depths. A coupled dynamic model of a wind turbine-tower-floating platform-mooring system is established, and the dynamic response of the platform, tensions in mooring lines, and bending moment at the tower base and blade root under four different mooring configurations are checked. A well-stabilized configuration (i.e., four vertical lines and 12 diagonal lines with an inclination angle of 30°) is selected to study the coupled dynamic responses of SFOWT with broken mooring lines, and in order to keep the safety of SFOWT under extreme sea-states, the pretension of the vertical mooring line has to increase from 1800–2780 kN. Results show that the optimized mooring system can provide larger restoring force, and the SFOWT has a smaller movement response under extreme sea-states; when the mooring lines in the upwind wave direction are broken, an increased motion response of the platform will be caused. However, there is no slack in the remaining mooring lines, and the SFOWT still has enough stability.

Numerical Sloshing Analysis of FLNG and LNGC Considering Two-Body Motion Effect

2011 ◽  
Author(s):  
Jong Jin Park ◽  
Hiroshi Kawabe ◽  
Mun Sung Kim ◽  
Byung Woo Kim ◽  
Jae Kwang Eom
Keyword(s):  
Numerical Model ◽  
Frequency Domain ◽  
Potential Theory ◽  
Three Dimensional ◽  
Coupled Model ◽  
Ship Motion ◽  
Body Motion ◽  
Liquid Motion ◽  
Motion Effect

Side by Side arrangement is considered for the LNG-FPSO offloading operations. In that case, two-body coupled effects are important for LNG-FPSO and LNGC motion and sloshing analysis. The present study is concerned with a ship motion and sloshing analysis considering two-body motion and sloshing-motion coupled effects. The methodology is based on three-dimensional potential theory on a coupled model of LNG-FPSO and LNGC in the frequency domain. To calculation sloshing impact pressures, the violent liquid motion inside tank is treated with three-dimensional numerical model adopting SOLA-VOF scheme.

Effects of the Initial Consolidation on the 3D Wave-Induced Seabed Response Around a Pile

2017 ◽  
Author(s):  
Jian Ding ◽  
Titi Sui ◽  
Chi Zhang ◽  
Yuan Li
Keyword(s):  
Numerical Model ◽  
Dynamic Response ◽  
Numerical Simulations ◽  
Normal Stress ◽  
Pile Foundation ◽  
Three Dimensional ◽  
Model Application ◽  
Effective Normal Stress ◽  
Wave Induced ◽  
Simulation Condition

Seabed consolidation state could be seen as the initial simulation condition for numerically simulating wave-induced seabed response. In this study, based on a three dimensional numerical model, effects of initial consolidation state on the 3D wave-induced unsaturated seabed response around mono-pile were investigated. By model application, the consolidation state of seabed around the pile foundation was described. Two common calculation approaches (seabed consolidation is considered or not) for wave-induced seabed response were compared by describing the distributions pattern of soil effective stresses and pore pressures around the pile. Significance of the consolidation state on seabed dynamic response against distances to pile was also carefully addressed. Numerical simulations indicated (1) the initial consolidation significantly increases the vertical effective normal stress in the vicinity of pile, (2) effects of the initial seabed consolidation on the wave-induced seabed response decrease with the increasing distance to the pile. This study suggests the initial consolidation should be considered in assessing the seabed stability for the design of the mono-pile foundation.

Experimental and Numerical Study on Large Truncation of Deepwater Mooring Line

2009 ◽  
Author(s):  
Yihua Su ◽  
Jianmin Yang ◽  
Longfei Xiao ◽  
Gang Chen
Keyword(s):  
Dynamic Response ◽  
Water Depth ◽  
Numerical Study ◽  
Unit Length ◽  
Low Frequency ◽  
Model Tests ◽  
Mooring Line ◽  
Mooring System ◽  
Mooring Lines ◽  
Wave Basin

Modeling the deepwater mooring system in present available basin using standard Froude scaling at an acceptable scale presents new challenges. A prospective method is to truncate the full-depth mooring lines and find an equivalent truncated mooring system that can reproduce both static and dynamic response of the full-depth mooring system, but large truncation arise if the water depth where the deepwater platform located is very deep or the available water depth of the basin is shallow. A Cell-Truss Spar operated in 1500m water depth is calibrated in a wave basin with 4m water depth. Large truncation arises even though a small model scale 1:100 is chosen. A series of truncated mooring lines are designed and investigated through numerical simulations, single line model tests and coupled wave basin model tests. It is found that dynamic response of the truncated mooring line can be enlarged by using larger diameter and mass per unit length in air. Although the truncated mooring line with clump presents a “taut” shape, its dynamic characteristics is dominated by the geometry stiffness and it underestimates dynamic response of the full-depth mooring line, even induces high-frequency dynamic response. There are still two obstacles in realizing dynamic similarity for the largely truncated mooring system: lower mean value of the top tension of upstream mooring lines, and smaller low-frequency mooring-induced damping.

Motion Responses of a Catenary-Taut-Hybrid Moored Single Module of a Semisubmersible Very Large Floating Structure in Multisloped Seabed

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Yiting Wang ◽  
Xuefeng Wang ◽  
Shengwen Xu ◽  
Lei Wang
Keyword(s):  
Shallow Water ◽  
Time Domain ◽  
Large Scale ◽  
Bottom Topography ◽  
Three Dimensional ◽  
Low Frequency ◽  
Mooring System ◽  
Floating Structure ◽  
Mooring Lines ◽  
Motion Responses

Motion responses of moored very large floating structures (VLFSs) in coastal regions are remarkably influenced by shallow water, seabed topography, and mooring system, which were given particular focus in this paper. A three-dimensional (3D) numerical model of a moored semisubmersible single module (SMOD) was described, and time domain simulated and experimentally validated. A catenary-taut-hybrid mooring system was adopted considering coastal space limitations. Large-scale catenary mooring lines were deployed on the deep water side, while taut chains were used on the shore side to decrease the anchor radius. Although the mooring system may induce a stiffness difference between the two sides, the effectiveness of the mooring system was demonstrated by time-domain simulation and model tests. The moored semisubmersible SMOD in shallow water exhibits significant low frequency characteristics. Water depth, asymmetric stiffness, and bottom topography effects were investigated by a series of sensitivity studies. The results show that these factors play an important role in motion responses of the moored SMOD, which can further conduce to better understandings on the hydrodynamic of the semisubmersible-type VLFSs.

scholarly journals Dynamic Analysis of Embedded Chains in Mooring Line for Fish Cage System

2018 ◽  
Vol 25 (4) ◽  
pp. 83-97
Author(s):  
Hui-Min Hou ◽  
Guo-Hai Dong ◽  
Tiao-Jian Xu ◽  
Yun-Peng Zhao ◽  
Chun-Wei Bi
Keyword(s):  
Numerical Model ◽  
Dynamic Response ◽  
Single Point ◽  
Mooring Line ◽  
Mooring System ◽  
Lumped Mass ◽  
Model Case ◽  
Cage System ◽  
Net Cage ◽  
Offshore Aquaculture

Abstract Investigation of the embedded chains in soil starts to play an important role in understanding the structural performance of mooring system, when the embedded anchors will be employed to sustain large loads with the gradually growth of installation depth of offshore aquaculture farm. The aim of this study is to investigate the dynamic response of mooring line considering the influence of embedded chains in clay soil for net cage system. Lumped-mass method is used to establish the numerical model for evaluating the performance of mooring line with embedded chains. To validate the numerical model, comparisons of numerical results with the analytical formulas and the experimental data are conducted. A good agreement of the profile and the tension response is obtained. Then, the effect of embedded chains on the static and dynamic response of mooring line is evaluated, and the dynamic behavior of mooring system considering embedded chains for net cage system is investigated. The results indicate that the soil resistance on embedded chains should be included to predict the mooring line development and the load on the embedded anchors in the numerical simulations. An appropriate safety factor should be included if employing the simplified model Case C at the initial design phase. And the effect of embedded chains on the holding capacity of embedded anchors in single-point mooring system for single net cage cannot be negligible during the design and operation phases. Consequently, it is profound to take into account the interaction of embedded chains and soil for accurately predicting the reliability of mooring system for fish cage.

Numerical Analysis of a Vessel-Shaped Offshore Fish Farm

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Lin Li ◽  
Zhiyu Jiang ◽  
Andreas Vangdal Høiland ◽  
Muk Chen Ong
Keyword(s):  
Wind Waves ◽  
Single Point ◽  
Fish Farm ◽  
Mooring Line ◽  
Mooring System ◽  
Wave Loads ◽  
Fish Farms ◽  
Mooring Lines ◽  
Environmental Loads ◽  
Fish Cages

The aquaculture industry is aiming to move fish farms from nearshore areas to open seas because of many attractive advantages in the open water. However, one major challenge is to design the structure to withstand the environmental loads due to wind, waves, and currents. The purpose of this paper is to study a vessel-shaped fish farm concept for open sea applications. The structure includes a vessel-shaped hull, a mooring system, and fish cages. The shape of the hull minimizes the wave loads coming from the bow, and the single-point mooring system is connected to the turret at the vessel bow. Such a system allows the whole fish farm to rotate freely about the turret, reduces the environmental loads on the structure and increases the spread area of fish wastes. A basic geometry of the vessel hull was considered and the hydrodynamic properties were obtained from the frequency-domain (FD) analysis. A mooring system with six mooring lines was designed to avoid possible interactions with the fish cages. Time-domain (TD) simulations were performed by coupling the hull with the mooring system. A simplified rigid model of the fish cages was considered. The global responses of the system and the mooring line loads were compared under various wave and current conditions. The effects due to misalignment of wave and current directions on the responses were discussed. Finally, the responses using flexible and rigid net models were compared under steady current conditions.

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