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1
Peters, Donald B., John N. Kemp, and Albert J. Plueddemann. "Coastal Surface Mooring Developments for the Ocean Observatories Initiative (OOI)." Marine Technology Society Journal 56, no. 6 (December 15, 2022): 70–74. http://dx.doi.org/10.4031/mtsj.56.6.2.
Повний текст джерелаАнотація:
Abstract Multiple mooring components have been developed at Woods Hole Oceanographic Institution (WHOI) that represent significant advancements in mooring technology. The Ocean Observatories Initiative (OOI) Coastal Surface Moorings are a unique coalescence of these elements into a robust and capable electromechanical mooring design. This paper describes innovative design elements in three key areas that are used operationally on OOI moorings: (1) components at the interface between buoy base and mooring riser, (2) electro-mechanical mooring riser components, and (3) an integrated seafloor anchor and instrument frame. These elements work together as a system that not only provides the necessary mechanical integrity for the mooring, but also provides mounting points for instrumentation and a reliable electrical pathway from the surface to the seafloor.
2
Wood, S. L., and R. A. Skop. "Architecture of an Expert System for Oceanographic Mooring Design." Journal of Offshore Mechanics and Arctic Engineering 111, no. 2 (May 1, 1989): 138–43. http://dx.doi.org/10.1115/1.3257087.
Повний текст джерелаАнотація:
Methods for the design and analysis of oceanographic moorings are well established (Berteaux, 1976). However, as with most engineering design problems, there are certain “rules-of-thumb” or “tricks-of-the-trade” that streamline the design process and enhance the performance of the final product. These rules-of-thumb are normally known to only a small cadre of people—experts—who have deep involvement and experience in the particular engineering design problem. These rules-of-thumb and other knowledge of several experts are incorporated to develop the fundamental architecture of an expert system for the design of single-point, subsurface, oceanographic moorings. Such moorings are used worldwide to collect oceanographic and acoustic data. The projected end user of this expert system is the oceanographer or acoustician who wishes to design and/or cost out a mooring but has not the access to or support for a mooring design group.
3
De Robertis, Alex, Robert Levine, and Christopher D. Wilson. "Can a bottom-moored echo sounder array provide a survey-comparable index of abundance?" Canadian Journal of Fisheries and Aquatic Sciences 75, no. 4 (April 2018): 629–40. http://dx.doi.org/10.1139/cjfas-2017-0013.
Повний текст джерелаАнотація:
A small number of stationary echo sounders have the potential to produce abundance indices where fish repeatedly occupy localized areas (e.g., spawning grounds). To investigate this possibility, we deployed three trawl-resistant moorings with a newly designed autonomous echo sounder for ∼85 days during the walleye pollock (Gadus chalcogrammus) spawning season in Shelikof Strait, Alaska. Backscatter observed from the moorings was highly correlated with ship-based acoustic surveys, suggesting that the mooring observations reflect abundance over much larger areas than the observation volume of the acoustic beam. A retrospective analysis of a 19-year time series of prespawning walleye pollock surveys was used to select mooring locations and determine that three to five moorings can produce an index of walleye pollock backscatter comparable to that produced by a ship-based survey covering ∼18 000 km2 (mean prediction error of <11% for five moorings). The three moorings deployed in Shelikof Strait yielded a backscatter estimate that was within ∼15%–20% of that observed during the survey. Thus, it appears feasible to design a relatively sparse mooring array to provide abundance information and other aspects of fish behavior in this environment.
4
Kwan, C. T. "Design Practice for Mooring of Floating Production Systems." Marine Technology and SNAME News 28, no. 01 (January 1, 1991): 30–38. http://dx.doi.org/10.5957/mt1.1991.28.1.30.
Повний текст джерелаАнотація:
A draft "API Recommended Practice for Design, Analysis, and Maintenance of Mooring for Floating Production Systems" was developed recently by the API Task Group on Mooring Design for Floating Structures. This document is closely related to API RP-2P, "Recommended Practice for the Analysis of Spread Mooring Systems for Floating Drilling Units." because both documents address mooring of floating units. However, this document is also different in many ways from API RP-2P because there are significant differences between a floating drilling mooring system and a floating production mooring system. Major differences of this document from API RP-2P are:The design environment is significantly more severe.Dynamic instead of quasistatic mooring analysis is recommended; tension limits are relaxed.Guidelines for thruster-assisted mooring are included.Fatigue analysis is required. In the course of developing the Draft RP, the API Task Group has done some fundamental work to establish a rational design practice for FPS mooring systems. This paper highlights the new design practice, presents its basis, and points out areas where future work is needed.
5
Kery, Sean. "Dynamic Modeling of Ship-to-Ship and Ship-to-Pier Mooring Performance." Marine Technology Society Journal 52, no. 5 (September 1, 2018): 87–93. http://dx.doi.org/10.4031/mtsj.52.5.10.
Повний текст джерелаАнотація:
AbstractTraditional methods for the design of ship-to-pier moorings in normal and storm conditions and for ship-to-ship moorings under normal conditions are currently based on static calculations. These calculations have served well for many years, first with natural fiber ropes and later with nylon and other low- to medium-modulus synthetics. Key to the success of this simplistic approach is lines that can elongate enough under tension to share the loads between multiple lines. When wire rope mooring lines are introduced, an increased weight catenary and the use of constant tension winches allowed enough compliance for the moorings to load share successfully.Now, we have very lightweight, high-modulus synthetic lines like High Modulus Polyethylene (HMPE), Aramid, and Liquid Crystal Polymer (LCP), where there is almost no stretch and very little weight to form a weight catenary. When used with constant tension winches that allow the mooring load to be shared across multiple lines, these can work well. However, when they are used from bollard to chock to bit with no compliance, they are unable to share the load between multiple lines, and high tension failures occur where a weaker but more compliant mooring line would be fine.This article describes advanced dynamic modeling of ships loaded by wind, waves, and currents in these conditions and the tension sharing between mooring lines of different materials and constructions. The need to share the mooring load between multiple lines is the crux of the issue.
6
Boo, Sung Youn, and Steffen Allan Shelley. "Design and Analysis of a Mooring Buoy for a Floating Arrayed WEC Platform." Processes 9, no. 8 (August 10, 2021): 1390. http://dx.doi.org/10.3390/pr9081390.
Повний текст джерелаАнотація:
This paper presents the design and analysis of a mooring buoy and its mooring systems to moor a floating platform mounting an arrayed Wave Energy Converters (WECs). The mooring buoy allows the WEC platform to weathervane around the mooring buoy freely by the prevailing environment directions, which enables consistent power generation. The WEC platform is connected to the buoy with synthetic hawsers, while station-keeping of the buoy is maintained with catenary mooring lines of chains tied to the buoy keel. The buoy also accommodates a power cable to transfer the electricity from the WEC platform to the shore. The WEC platform is designed to produce a total of 1.0 MW with multiple WECs installed in an array. Fully coupled time-domain analyses are conducted under the site sea states, including extreme 50 y and survival 100 y conditions. The buoy motions, mooring tensions and other design parameters are evaluated. Strength and fatigue designs of the mooring systems are validated with requirements according to industry standards. Global and local structural designs of the mooring buoy are carried out and confirm the design compliances.
7
Nielsen, Kim, and Jonas Thomsen. "KNSwing—On the Mooring Loads of a Ship-Like Wave Energy Converter." Journal of Marine Science and Engineering 7, no. 2 (February 1, 2019): 29. http://dx.doi.org/10.3390/jmse7020029.
Повний текст джерелаАнотація:
The critical function of keeping a floating Wave Energy Converter in position is done by a mooring system. Several WECs have been lost due to failed moorings, indicating that extreme loads, reliability and durability are very important aspects. An understanding of the interaction between the WEC’s motion in large waves and the maximum mooring loads can be gained by investigating the system at model scale supported by numerical models. This paper describes the testing of a novel attenuator WEC design called KNSwing. It is shaped like a ship facing the waves with its bow, which results in low mooring loads and small motions in most wave conditions when the structure is longer than the waves. The concept is tested using an experimental model at scale 1:80 in regular and irregular waves, moored using rubber bands to simulate synthetic moorings. The experimental results are compared to numerical simulations done using the OrcaFlex software. The experimental results show that the WEC and the mooring system survives well, even under extreme and breaking waves. The numerical model coefficient concerning the nonlinear drag term for the surge motion is validated using decay tests. The numerical results compare well to the experiments and, thereby, the numerical model can be further used to optimize the mooring system.
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Shi, Ji Wei, Hong Yuan Li, and Bing Zhen Li. "The Design of the Hawse Pipe and Intelligent Positioning." Advanced Materials Research 912-914 (April 2014): 824–28. http://dx.doi.org/10.4028/www.scientific.net/amr.912-914.824.
Повний текст джерелаАнотація:
The ship mooring system is an important installation for anchoring, the performance of ship mooring system affects the safety operation of the ship. Hawse pipe arrangement is the most important part of the ship mooring equipment layout design, the hawse pipe layout will directly affect the feasibility and convenience of ship mooring system in use. During traditional ship mooring equipment layout design, designers should firstly calculate the outfitting number, and inspect the specification manually to select mooring equipments, then design the hawse pipe layout with their experience by hand. In the previous ship mooring design work, the work efficiency is low. If ship line or general layout changes, designers need to re-check the mooring function and once mooring system can't meet the requirements, they need to re-design. This affects the overall design of the ship adversely. This paper is based on CAD platform, it researches the ship mooring system especially the hawse pipe intelligent layout design. Through using computer programs, drawing the hawse pipe section automatically and selecting optimal layout of the hawse pipe is achieved. This method improved the rationality of the design of the ship mooring system arrangement. This method can reduce the traditional burden of manually inspecting, and make the hawse pipe layout design more efficient.
9
Pan, Qi, and Po Wen Cheng. "Cost-based mooring designs and a parametric study of bridles for a 15 MW spar-type floating offshore wind turbine." Journal of Physics: Conference Series 2265, no. 4 (May 1, 2022): 042013. http://dx.doi.org/10.1088/1742-6596/2265/4/042013.
Повний текст джерелаАнотація:
Abstract This paper highlights a cost-based design method for feasible and cost-effective mooring configurations. A parametric study of mooring designs considering bridle impact is performed for a 15 MW spar-type floating offshore wind turbine (FOWT). This site-specific FOWT is based on the preliminary model from EU funded H2020 Project COREWIND. Without running numerical simulations, the cost-based design method generates 1443 mooring configurations with normalized costs ranging from 1.00 to 1.667. Six configurations with the lowest normalized costs are selected for OpenFAST simulations. The ultimate test results verify the structural strength of mooring configurations. Bridle designs cause significant impact on the ultimate mooring tensions and floater motions in surge, sway and yaw, which is clearly influenced by the mass ratio of a bridle to a mooring line. When the mass ratio decreases from 13% to 5%, peak mooring tensions increase by up to 17%. The influence of bridle designs on mooring tension fatigue is less prominent and the effect of mass ratio on mooring fatigue varies with wind speed. Near the rated wind speed, deviations in mooring fatigue loads are within 5% for all six configurations. This cost-based method promotes feasible and economical mooring designs. The parametric study of bridle designs provides solid support for optimal mooring designs of spar-type FOWTs.
10
Gözcü, Ozan, Stavros Kontos, and Henrik Bredmose. "Dynamics of two floating wind turbines with shared anchor and mooring lines." Journal of Physics: Conference Series 2265, no. 4 (May 1, 2022): 042026. http://dx.doi.org/10.1088/1742-6596/2265/4/042026.
Повний текст джерелаАнотація:
Abstract Floating wind farms present the opportunity to harvest wind resources located in deep water sites. Shared mooring designs can contribute in making floating wind energy more cost-competitive, and it is important to understand the new system dynamics that arise. We are presenting here HAWC2Farm, an extension of HAWC2 that can model multiple wind turbines with shared mooring lines. We apply the new modeling capabilities to simulate two 15 MW floating wind turbines on spar floaters with shared mooring lines. We consider two different sites and we identify and compare the natural frequencies and mode shapes of the shared mooring designs with those of an individual moored turbine. Furthermore, we investigate the influence of design parameters on the systems’ natural frequencies and we show that it is possible for a shared mooring design to achieve similar characteristics as a single turbine design. Finally, we test the response of the shared mooring design in steady wind and regular waves and find that the surge displacement of the upstream turbine and its mooring line loads are considerably larger compared to the single turbine case.
11
Oppenheim, B. W. "Interactive Design and Operations of Moorings." Journal of Offshore Mechanics and Arctic Engineering 111, no. 4 (November 1, 1989): 311–17. http://dx.doi.org/10.1115/1.3257100.
Повний текст джерелаАнотація:
This paper describes a stand-alone PC-based computer simulator for mooring design and operations. Both program logic and mathematics are discussed. Competing algorithms for solving several classical mooring problems are compared. The program contains a design module, static and dynamic mooring simulators, and mooring calculator modules. The design module performs an automatic optimum design of anchor deployment for any environmental condition, or allows the user to perform an interactive design. The static simulator predicts system responses in all mooring operations. The dynamic simulator is an implementation of the recent requirement of regulatory bodies for simulating slow-drifting motions of the vessel after a line failure. The calculator includes modules that compute weather forces, system stiffness, elastic catenary mechanics, and others. The program is interactive, menu-driven, and includes graphics.
12
Wang, Zhuo, Timothy J. McCarthy, and M. Neaz Sheikh. "Application of Multiple Objective Particle Swarm Optimisation in the Design of Damaged Offshore Mooring Systems." Key Engineering Materials 569-570 (July 2013): 1257–64. http://dx.doi.org/10.4028/www.scientific.net/kem.569-570.1257.
Повний текст джерелаАнотація:
The offshore hydrocarbon industry operates in more hostile environments as more of marginal fields become economically viable. This means that more floating production systems and economical mooring systems will be needed. With this increase in the use of marginal fields goes the need to re-use vessels and moorings. Floating production systems, such as FPSOs, need to survive extreme events and extreme damage conditions. When one mooring line is damaged, the remaining ones must be sufficient to avoid a complete failure and still protect critical components such as the riser. This paper looks into applying an evolutionary optimisation technique, namely multiple objective particle swarm optimisation, to the damaged mooring design and analysis. The evaluation of offshore objective functions is computationally expensive since it requires use of complex simulations. When the number of objective function evaluations is large, as is the case with evolutionary methods, even a fast computer takes undesirably long to complete the job. Hence, a robust optimisation algorithm with great efficiency is required to minimise the number of total runs.
13
Ren, Hui Long, Jia Xing Zou, and Guang Ping Zou. "Mooring System Waterdepth Design of Considering Stiffness and Drift Angle Analysis." Applied Mechanics and Materials 556-562 (May 2014): 817–21. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.817.
Повний текст джерелаАнотація:
The mooring system initial design is quasi-static method based on catenary method. The mooring line stiffness derivation also base on catenary method. In the paper, using jumping wire of high voltage cable calculation method, design the mooring system. Building initial design model, considering the mooring line stiffness and drift angle of mooring line and structure.
14
Hall, Matthew, Ericka Lozon, Stein Housner, and Senu Sirnivas. "Design and analysis of a ten-turbine floating wind farm with shared mooring lines." Journal of Physics: Conference Series 2362, no. 1 (November 1, 2022): 012016. http://dx.doi.org/10.1088/1742-6596/2362/1/012016.
Повний текст джерелаАнотація:
This paper discusses the development and analysis of a novel design for a 10-turbine floating wind farm with shared mooring lines. Shared mooring lines tether adjacent floating platforms together, reducing the number of anchors required but increasing system complexity. We present a systematic, multistage design process for shared mooring systems, involving linearized analysis of array layout options, quasi-static mooring line optimization, and design refinement based on coupled dynamic loads analysis. The design developed from this process is thought to represent one of the most advantageous shared-mooring configurations for this scale of floating wind array. It features perpendicular anchor line pairs and allows shared, multiline anchors, making it an example of a shared-mooring-and-anchor array. Comparing the performance and cost characteristics of the shared-mooring design with more conventional three-line individual mooring systems shows equivalent dynamic response characteristics and stationkeeping system cost savings of 25% when using shared mooring lines and shared anchors. The design is also advantageous in the case of a mooring line failure, with offsets and redundancy characteristics similar to four-line individual mooring systems.
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孙, 敬鹏. "The Design of Mooring System." Pure Mathematics 08, no. 03 (2018): 247–52. http://dx.doi.org/10.12677/pm.2018.83031.
Повний текст джерела
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Park, Hongrae, and Sungjun Jung. "Design and Automated Optimization of an Internal Turret Mooring System in the Frequency and Time Domain." Journal of Marine Science and Engineering 9, no. 6 (May 27, 2021): 581. http://dx.doi.org/10.3390/jmse9060581.
Повний текст джерелаАнотація:
A cost-effective mooring system design has been emphasized for traditional offshore industry applications and in the design of floating offshore wind turbines. The industry consensus regarding mooring system design is mainly inhibited by previous project experience. The design of the mooring system also requires a significant number of design cycles. To take aim at these challenges, this paper studies the application of an optimization algorithm to the Floating Production Storage and Offloading (FPSO) mooring system design with an internal turret system at deep-water locations. The goal is to minimize mooring system costs by satisfying constraints, and an objective function is defined as the minimum weight of the mooring system. Anchor loads, a floating body offset and mooring line tensions are defined as constraints. In the process of optimization, the mooring system is analyzed in terms of the frequency domain and time domain, and global and local optimization algorithms are also deployed towards reaching the optimum solution. Three cases are studied with the same initial conditions. The global and local optimization algorithms successfully find a feasible mooring system by reducing the mooring system cost by up to 52%.
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Zhang, Aobo, Zhenju Chuang, Shewen Liu, Xin Chang, Lixun Hou, Zhen He, and Shiqi Liu. "Research on Mooring System Design for Kulluk Platform in Arctic Region." Water 14, no. 11 (May 30, 2022): 1762. http://dx.doi.org/10.3390/w14111762.
Повний текст джерелаАнотація:
Mooring system design of a floating offshore structure in the arctic region is considered to be extremely important. This paper aims at investigating an optimal mooring system for the Kulluk platform operating in the Beaufort Sea, which has ice-free and ice-covered conditions during the whole year time. In order to complete the layout design of the mooring system to satisfy the year-round operation, both the effect of wave loads and ice loads should be considered. The research establishes a coupled numerical production system composed of the Kulluk platform and mooring system. Wave load is solved by potential flow theory. The slender finite element method is used to compute the tension of the mooring system. The nonlinear finite element method, discrete element method, and empirical formula are compared to analyze ice load. Finally, the discrete element method is selected for the analysis of the Kulluk, and the simulated results are compared reasonably with the field data. When studying the mooring line configurations, quantitative time-domain analysis is carried out, including tension of mooring lines and the motions of the platform under different working conditions. The research work in this paper will provide a reference for the optimal design of the mooring system of the platform operating in the Arctic Sea.
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Fredriksson, David W., Erik Muller, Kenneth Baldwin, M. Robinson Swift, and Barbaros Celikkol. "Open Ocean Aquaculture Engineering: System Design and Physical Modeling." Marine Technology Society Journal 34, no. 1 (January 1, 2000): 41–52. http://dx.doi.org/10.4031/mtsj.34.1.5.
Повний текст джерелаАнотація:
An open ocean aquaculture net pen system was developed and deployed for an exposed demonstration site south of the Isles of Shoals, New Hampshire in 55 meters of water. This component of the project is part of an interdisciplinary effort at the University of New Hampshire involving engineers, biologists, economists and commercial fishermen. Initially, two cages were specified for the growout of summer flounder (Paralichthys dentatus). The design process included physical model testing conducted in a wave/tow tank using 1/22.5 scale models. To select an optimum system, experiments were performed using gravity-type and central spar-type cages. Vertical taut line and catenary moorings were evaluated. Data acquisition included drag and wave forces on the cages, mooring line forces and heave, pitch and surge motion of the cages.After comparison of the results and holding a design review including outside experts, a central spar configuration was selected for both cages. This system exhibited both reduced force loadings and less extreme motion, and its rigid frame would resist volume changes under storm conditions. In the final mooring design, each cage was separately deployed using a four anchor system to ensure redundancy. A mid-depth, square, horizontal grid was employed in order to reduce anchor footprint area, which is very expensive under New Hampshire permit rules. Mooring system components were sized to meet loadings scaled up from the physical model results. The system was deployed in June of 1999 and has performed well in all weather forcing conditions to date.
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Wang, Tian Ying, Li Jun Yang, Zhi Gang Xu, and Jin Kun Liu. "Design and Comparison of Catenary and Taut Mooring Systems for New Concept FPSO IQFP in Shallow Waters." Applied Mechanics and Materials 353-356 (August 2013): 2670–75. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.2670.
Повний текст джерелаАнотація:
In order to design an effective and economical multi-point mooring system for the new concept FPSO IQFP (fillet inverted quadrangular frustum pyramid shaped FPSO, presented by the lead author), the effects of the mooring parameters on the performance of catenary mooring system and taut mooring system were investigated according to the initial design plans given in advance according to the steady environment forces and practical experiences. Then, the optimal mooring systems were developed on the basis of the static analysis results combined with the coupled calculations in time domain. Finally, the merits and demerits of the two mooring schemes were compared based on the mooring and static characteristic parameters as well as the curves of restoring force against horizontal displacement of the catenary and taut mooring systems respectively. The results verify that the taut mooring system is preferable to the catenary mooring system for IQFP deployed in shallow waters.
20
Sholihin, Yoffan Ramadhan, and Haryo D. Armono. "The Design of Mooring Dolphin Layout and Mooring Line Tension Analysis." International Journal of Offshore and Coastal Engineeing 1, no. 1 (August 25, 2017): 22. http://dx.doi.org/10.12962/j2580-0914.v1i1.2871.
Повний текст джерела
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Huang, Wei-Hua, and Ray-Yeng Yang. "Water Depth Variation Influence on the Mooring Line Design for FOWT within Shallow Water Region." Journal of Marine Science and Engineering 9, no. 4 (April 12, 2021): 409. http://dx.doi.org/10.3390/jmse9040409.
Повний текст джерелаАнотація:
The objective of this paper was to present the modeling and optimization of mooring lines for floating offshore wind turbines (FOWT) located in various water depths from 50 m to 100 m in Taiwan western offshore areas. A semi-submersible floating wind turbine system is considered based on Offshore Code Comparison Collaborative Continuation (OC4) DeepCwind platform with the National Renewable Energy Laboratory (NREL) offshore 5-MW baseline wind turbine. The mooring lines proposed consist of a catenary mooring with studless chains. Three nominal sizes of the mooring chain links are taken into account with diameters of 95 mm, 115 mm and 135 mm. According to this configuration, a total of five mooring designs for different water depths (i.e., 50 m, 60 m, 70 m, 80 m, 100 m) are analyzed according to the rules and regulations of the two certification institutions, Det Norske Veritas (DNV) and American Petroleum Institute (API). Considering ultimate limit state (ULS), fatigue limit state (FLS) and maximum operating sea state (MOSS) based on a typhoon with a 50-year return period and current with a 10-year return period, 25-year design life, as well as 1-year return period, respectively, long-term predictions of breaking strength, fatigue and stability are performed. The software OrcaFlex version 10.3 d is used to simulate and design the mooring lines. The obtained results show that the shallow mooring design of 50 m water depth case presents the heaviest chains among the other water depths, increasing their mooring costs. On the other hand, the 100 m water design has much longer mooring lines, making this parameter the cost driving one. Thus, the minimum mooring cost range is from 60 m to 80 m water depth.
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Qiao, Dongsheng, Rizwan Haider, Jun Yan, Dezhi Ning, and Binbin Li. "Review of Wave Energy Converter and Design of Mooring System." Sustainability 12, no. 19 (October 7, 2020): 8251. http://dx.doi.org/10.3390/su12198251.
Повний текст джерелаАнотація:
In recent decades, the emphasis on renewable resources has grown considerably, leading to significant advances in the sector of wave energy. Nevertheless, the market cannot still be considered as commercialized, as there are still other obstacles in the mooring system for wave energy converters (WECs). The mooring system must be designed to not negatively impact the WEC’s efficiency and reduce the mooring loads. Firstly, the overview of the types of wave energy converters (WECs) are classified through operational principle, absorbing wave direction, location, and power take-off, respectively, and the power production analysis and design challenges of WECs are summarized. Then, the mooring materials, configurations, requirements, and the modeling approaches for WECs are introduced. Finally, the design of mooring systems, including the design considerations and standards, analysis models, software, current research focus, and challenges are discussed.
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West, William, Andrew Goupee, Spencer Hallowell, and Anthony Viselli. "Development of a Multi-Objective Optimization Tool for Screening Designs of Taut Synthetic Mooring Systems to Minimize Mooring Component Cost and Footprint." Modelling 2, no. 4 (December 8, 2021): 728–52. http://dx.doi.org/10.3390/modelling2040039.
Повний текст джерелаАнотація:
As the offshore wind industry develops, more lease sites in the intermediate water depth (50–85 m) are being released to developers. In these water depths floating wind turbines with chain catenary systems and fixed-bottom turbines with jacketed structures become cost prohibitive. As such, industry and researchers have shifted focus to floating turbines with taut or semi-taut synthetic rope mooring systems. In addition to reducing the cost of the mooring systems, synthetic systems can also reduce the footprint compared to a chain catenary system which frees areas around the turbine for other maritime uses such as commercial fishing. Both the mooring systems component cost and footprint are pertinent design criteria that lend themselves naturally to a multi-objective optimization routine. In this paper a new approach for efficiently screening the design space for plausible mooring systems that balance component cost and footprint using a multi-objective genetic algorithm is presented. This method uses a tiered-constraint method to avoid performing computationally expensive time domain simulations of mooring system designs that are infeasible. Performance metrics for assessing the constraints of candidate designs are performed using open-source software such as Mooring Analysis Program (MAP++), OpenFAST and MoorDyn. A case study is presented providing a Pareto-optimal design front for a taut synthetic mooring system of a 6-MW floating offshore wind turbine.
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Trolliet, Mélodie, and Lucien Wald. "Monthly solar radiation in the tropical Atlantic Ocean: Can its spatial variations be captured by the current configuration of the PIRATA moorings?" Advances in Science and Research 15 (July 11, 2018): 127–36. http://dx.doi.org/10.5194/asr-15-127-2018.
Повний текст джерелаАнотація:
Abstract. The present work aims at contributing to the proper design of networks of measuring moorings with regard to the downwelling solar irradiance at surface (DSIS). Considering the yearly profiles of the monthly DSIS, this article studies whether the 17 moorings within the existing PIRATA network are well geographically distributed so that they capture the spatial variations of the yearly profiles in the tropical Atlantic Ocean. A clustering technique is performed onto the HelioClim-3v5 satellite-derived gridded dataset of DSIS spanning 12 years, thus yielding 17 zones of similar yearly profiles. It was found that the mean yearly profiles of several zones are similar to the measured ones at the three moorings having enough measurements to perform the comparison. Zones have clear connections with the climatology of the region and circulation regimes. The geographical distribution of the moorings has been analysed with regard to the zoning. In the northern region of the tropical basin, each zone contains at least one PIRATA mooring. Hence, the configuration of the PIRATA network is appropriate to reflect the spatial variations of the yearly profiles in this northern part. In the southern basin, the coverage is less complete; several zones do not contain any PIRATA mooring. Thus, the network does not capture the spatial variations of the yearly profiles and this may induce misinterpretation of the PIRATA measurements at synoptic scales. It was also found that the computation of latitudinal or longitudinal averages of irradiance may be wrong if based solely on measurements from moorings without taking into account the spatial representativeness of a mooring.
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Prasetyawan, Ika, and Navik Puryantini. "Design Aspects of Positional Mooring System Based on LR FOIFL Rules." Wave: Jurnal Ilmiah Teknologi Maritim 6, no. 1 (January 24, 2019): 31–38. http://dx.doi.org/10.29122/jurnalwave.v6i1.3325.
Повний текст джерелаАнотація:
Floating offshore units, such as FPSOs, are subject to dynamic excitations from the environment and require to be moored to maintain position at the fix location of operation. In designing positional mooring systems for floating offshore units, systematic analyses must be performed to predict tension levels in the mooring lines and offsets of the floating unit under extreme and ambient service conditions, in order to ensure the mooring arrangement provides a level of safety acceptable to the industry. In order to derive environmental loads pertinent to the location of operation, environmental data should be made available comprising of long and short term current, wind and wave characteristic data specific to the site of operation. Based on LR FOIFL Rules, the performance of positional mooring systems is assessed on the basis of sets of site specific extreme and ambient (or fatigue) environmental conditions. Class rules require consideration of extreme conditions with recurrence period of 100 years (e.g. combination of 100 year waves + 100 year wind + 10 year current).In the process of designing positional mooring systems of FPSOs, designers may start from quasi-static analysis at preliminary design stage, and then investigate various combinations of extreme conditions in the dynamic analysis for a more rigorous approach during the final design stage.The outcomes of the analyses have to be compared against industry standards such as the LR FOIFL rules to confirm the positional mooring system’s design meets levels of safety recognised as acceptable to the industry. In this paper, an introduction to positional mooring systems for FPSOs, considering typical strength aspects is given, followed by a general description of hydrodynamic characteristics of ship shape FPSOs The design aspects of mooring system is then given in section outlining methodology in mooring analysis using either quasi-static or dynamic method.
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Qiao, Dong Sheng, and Jin Ping Ou. "Parameter Calculation of Viscous Damper Applied in the Truncated Model Test Design of a Deepwater Semi-Submersible Platform." Advanced Materials Research 168-170 (December 2010): 1480–85. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.1480.
Повний текст джерелаАнотація:
In the equivalent water depth truncated model test design of a deepwater semi-submersible platform, the viscous damper is designed to simulate the contribution of mooring damping to total damping of floating platform. The dissipated energy by a mooring line from the floating platform as a result of its oscillation is applied to calculate the mooring-induced damping. The mooring line and seabed interaction is based on the hypothesis of rigid seabed. The fluid drag force and inertia force on the mooring line are calculated according to the Morrison formula. The non-liner dynamic analysis of mooring line is executed in the time domain based on the finite element method. The mooring induced damping is obtained from the results. The value difference of mooring induced damping between the truncated and full-depth mooring line is linearized to provide parameter for the design of viscous damper.
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Schulz, E. W., M. A. Grosenbaugh, L. Pender, D. J. M. Greenslade, and T. W. Trull. "Mooring Design Using Wave-State Estimate from the Southern Ocean." Journal of Atmospheric and Oceanic Technology 28, no. 10 (October 1, 2011): 1351–60. http://dx.doi.org/10.1175/jtech-d-10-05033.1.
Повний текст джерелаАнотація:
Abstract The Southern Ocean Flux Station was deployed near 47°S, 140°E. The extreme wind and wave conditions at this location require appropriate mooring design, which includes dynamic fatigue analysis and static analysis. An accurate estimate of the wave conditions was essential. A motion reference unit was deployed in a nearby test mooring for 6 months. The motion data provided estimates of significant wave height that agreed well with the Australian Bureau of Meteorology wave model, increasing confidence in the model performance in the Southern Ocean. The results of the dynamic fatigue analysis using three input wave datasets and implications for the mooring design are described. The design analysis predicts the fatigue life for critical mooring components and guided the final selection of links and chain shackles. The three input wave climatologies do not differ greatly, and this is reflected in minimal changes to mooring components for each of the fatigue analyses.
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Garza-Rios, Luis O., Michael M. Bernitsas, Kazuo Nishimoto, and Joa˜o Paulo J. Matsuura. "Dynamics of Spread Mooring Systems With Hybrid Mooring Lines." Journal of Offshore Mechanics and Arctic Engineering 122, no. 4 (July 19, 2000): 274–81. http://dx.doi.org/10.1115/1.1315591.
Повний текст джерелаАнотація:
The weight of a chain mooring line in deep water is the main source of mooring line tension. Chain weight also induces a vertical force on the moored vessel. To achieve the desired tension without excessive weight, hybrid mooring lines, such as lighter synthetic fiber ropes with chains, have been proposed. In this paper, the University of Michigan methodology for design of mooring systems is developed to study hybrid line mooring. The effects of hybrid lines on the slow-motion nonlinear dynamics of spread mooring systems (SMS) are revealed. Stability analysis and bifurcation theory are used to determine the changes in SMS dynamics in deep water based on pretension and angle of inclination of the mooring lines for different water depths and synthetic rope materials. Catastrophe sets in two-dimensional parametric design spaces are developed from bifurcation boundaries, which delineate regions of qualitatively different dynamics. Stability analysis defines the morphogeneses occurring as bifurcation boundaries are crossed. The mathematical model of the moored vessel consists of the horizontal plane—surge, sway, and yaw—fifth-order, large drift angle, low-speed maneuvering equations. Mooring lines are modeled quasistatically as nonlinear elastic strings for synthetic ropes and as catenaries for chains, and include nonlinear drag and touchdown. Excitation consists of steady current, wind, and mean wave drift. Numerical applications are limited to steady current, which is adequate for revealing the SMS design depending on the selected parameters. [S0892-7219(00)00804-9]
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Isaacson, Michael, and Ronald Byres. "FLOATING BREAKWATER RESPONSE TO WAVE ACTION." Coastal Engineering Proceedings 1, no. 21 (January 29, 1988): 162. http://dx.doi.org/10.9753/icce.v21.162.
Повний текст джерелаАнотація:
The present paper describes a study carried out to investigate floating breakwater behavior in waves. Components of the study include a field survey of floating breakwaters in British Columbia, Canada, the development of a numerical model of breakwater behavior and the experimental testing of a particular breakwater design. The numerical model has been developed to provide breakwater motions, transmission coefficients and mooring forces. The model combines linear diffraction theory for obliquely incident waves, a mooring analysis, the inclusion of viscous damping coefficients obtained from experimental or field data, and the inclusion of drag and wave drift forces for use in the static analysis of the moorings. The experiments were carried out with normally incident regular waves of different heights and periods. Preliminary results indicate that the numerical model should prove to be a useful tool in floating breakwater design.
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Martinelli, Luca, Piero Ruol, and Giampaolo Cortellazzo. "ON MOORING DESIGN OF WAVE ENERGY CONVERTERS: THE SEABREATH APPLICATION." Coastal Engineering Proceedings 1, no. 33 (October 15, 2012): 3. http://dx.doi.org/10.9753/icce.v33.structures.3.
Повний текст джерелаАнотація:
The design of a mooring system of a Wave Energy Converter is a challenging process that points out several unsolved technical problems, mostly related to the highly non-linear hydrodynamic phenomena occurring when high waves (e.g. 8 m high with 200 m wavelength) propagate in relatively shallow waters (e.g. 20 m). The aim of this note is to point out the relevance of the non-linear response of a WEC anchored in relatively shallow waters (shallow in the “non-linear” sense) in terms of loads applied to the mooring lines. Further, the effects of this cyclic load on the anchors is investigated. Note that to some extent it is like checking the importance of geotechnical and coastal engineers in the design process of the WEC structure and its mooring system (typically carried out by naval architects). The whole mooring design process is first outlined and then it is schematically applied to a specific case, namely a promising Italian device named SeaBreath (www.seabreath.it), in view of a possible deployment in the Adriatic Sea. The main concern of mooring designers is related to resonance effects induced by the second order drift. Therefore specific tests have been carried out in the 36 m long x 1.0 m wide x 1.3 m high wave flume of Padova University. Tests focused on the forces on the mooring lines induced by the sum of two regular waves of similar frequency. The mooring design is still far from complete: the physical model proved the relevance of the aforementioned effects but a numerical investigation (not yet performed) is required to draw final conclusions.
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Bernitsas, M. M., and L. O. Garza-Rios. "Effect of Mooring Line Arrangement on the Dynamics of Spread Mooring Systems." Journal of Offshore Mechanics and Arctic Engineering 118, no. 1 (February 1, 1996): 7–20. http://dx.doi.org/10.1115/1.2828806.
Повний текст джерелаАнотація:
A design methodology is formulated to reveal the dependence of nonlinear slowmotion dynamics of spread mooring systems (SMS) on mooring line arrangement. For a given SMS configuration, catastrophe sets are developed in the parametric design space showing the dependence of stability boundaries and singularities of bifurcations on design variables. This approach eliminates the need for nonlinear simulations. For general SMS design, however, the designer relies on experience rather than scientific understanding of SMS nonlinear dynamics, due to the high number of design variables. Several numerical applications are used to demonstrate counterintuitive ways of improving SMS dynamics. The SMS design methodology formulated in this paper aims at providing fundamental understanding of the effects of mooring line arrangement and pretension on SMS horizontal plane dynamics. Thus, the first guidelines are developed to reduce trial and error in SMS design. The methodology is illustrated by comparing catastrophe sets for various SMS configurations with up to three mooring lines. Numerous examples for a barge and a tanker SMS which exhibit qualitatively different nonlinear dynamic behavior are provided.
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Xia, Liang-yu, Li Zhi, Ling Chen, and Yue Cheng. "Optimization Design and Calculation of Mooring System Parameters based on Genetic Algorithm." MATEC Web of Conferences 153 (2018): 07006. http://dx.doi.org/10.1051/matecconf/201815307006.
Повний текст джерелаАнотація:
Based on the static equilibrium model of mooring system parameters, the multi - objective optimization model is established and the genetic algorithm is introduced as the optimization algorithm, which improves the crossover operator. Taking the example of a single point mooring system, concerned optimization design and calculation has been done. Compared with the general genetic algorithm, the result of this algorithm is superior, significantly improving the stability of the mooring system.
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Zhou, Yiming, Sensen Feng, Xiaojiang Guo, Feng Tian, Xu Han, Wei Shi, and Xin Li. "Initial Design of a Novel Barge-Type Floating Offshore Wind Turbine in Shallow Water." Journal of Marine Science and Engineering 11, no. 3 (February 21, 2023): 464. http://dx.doi.org/10.3390/jmse11030464.
Повний текст джерелаАнотація:
The studies on floating offshore wind turbines (FOWTs) have been increasing over recent decades due to the growing interest in offshore renewable energy. The present paper proposes a barge platform with four moonpools to support the Technical University of Denmark 10 MW wind turbine for a designed water depth of 60 m. A 4 × 2 mooring system with eight mooring lines is also proposed for the barge platform. The main dimensions of the barge platform are optimally selected with respect to its preliminary hydrodynamic properties and potential financial benefit. The proposed barge-type FOWT is then demonstrated to be aligned with the DNV standard requirements in terms of its intact and damage stability. Furthermore, coupled time-domain simulations are conducted for the proposed barge FOWT with mooring under the selected environmental and operational conditions by using Simo-Riflex-AeroDyn (SRA). Through decay test simulations, the natural periods of the barge-type FOWT are demonstrated to be within the DNV recommended ranges. The proposed mooring system is also benchmarked with the 3 × 3 mooring concept that was used for a 3 MW barge-type FOWT installed in Kitakyushu. The response magnitudes of the barge platform and mooring line tension are similar to both mooring systems, and thus the 4 × 2 mooring system is preferred due to its lower cost. In addition, the proposed barge platform is preliminarily demonstrated to be able to survive for the 50-year extreme environmental conditions under parked wind turbine status, as well as the normal environmental conditions under the operating status.
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Wu, Jo-Ti, Jiahn-Horng Chen, Ching-Yeh Hsin, and Forng-Chen Chiu. "Dynamics of The FKT System with Different Mooring Lines." Polish Maritime Research 26, no. 1 (March 1, 2019): 20–29. http://dx.doi.org/10.2478/pomr-2019-0003.
Повний текст джерелаАнотація:
Abstract To harness the endless hydrokinetic energy of the Kuroshio current, the joint research team of the National Taiwan University and the National Taiwan Ocean University has developed a floating Kuroshio turbine (FKT) system in Taiwan. In normal operation, the system floats at a certain small depth from the ocean surface to reduce the wave effects and take advantage of faster current speeds. In the present study, the effect of the mooring line on the system dynamics is investigated computationally. Two different auxiliary mooring line designs and, for each design, three different common mooring lines (polyester ropes of neutral buoyancy, iron chains, and 6×19 wires ropes with wire core) are examined. The study makes use of several commercial and in-house packages, integrated to find various coefficients. It is found that the mooring line, the auxiliary mooring line design, and the gravity centre can have a significant effect on system fluctuations in normal operation if the combination of these factors is not properly matched.
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Bernitsas, M. M., and L. O. Garza-Rios. "Mooring System Design Based on Analytical Expressions of Catastrophes of Slow-Motion Dynamics." Journal of Offshore Mechanics and Arctic Engineering 119, no. 2 (May 1, 1997): 86–95. http://dx.doi.org/10.1115/1.2829058.
Повний текст джерелаАнотація:
Analytical expressions of the necessary and sufficient conditions for stability of mooring systems representing bifurcation boundaries, and expressions defining the morphogeneses occurring across boundaries are presented. These expressions provide means for evaluating the stability of a mooring system around an equilibrium position and constructing catastrophe sets in any parametric design space. These expressions allow the designer to select appropriate values for the mooring parameters without resorting to trial and error. A number of realistic applications are provided for barge and tanker mooring systems which exhibit qualitatively different nonlinear dynamics. The mathematical model consists of the nonlinear, third-order maneuvering equations of the horizontal plane slow-motion dynamics of a vessel moored to one or more terminals. Mooring lines are modeled by synthetic nylon ropes, chains, or steel cables. External excitation consists of time-independent current, wind, and mean wave drift forces. The analytical expressions presented in this paper apply to nylon ropes and current excitation. Expressions for other combinations of lines and excitation can be derived.
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Du, Yu, Wen Hua Wu, and Qian Jin Yue. "Method for Tensile Measurement of Stud-Less Mooring Chain." Advanced Materials Research 718-720 (July 2013): 703–8. http://dx.doi.org/10.4028/www.scientific.net/amr.718-720.703.
Повний текст джерелаАнотація:
Tension of mooring chain is the principle characteristic for mooring system. Tensile value which derived from on-site mooring lines could be used for risk assessment, design evaluation etc. It is hard to obtain underwater tension of mooring chain by traditional method, such as strain gauge, FBG, etc. A new tensile measure method is present based on finite element analysis and shape characteristics of stud-less mooring chain. At first, deformation of stud-less mooring chains is analyzed by finite element method and Ansys software. Then, a design of tension-meter is developed on the basis of the deformation characteristic due to the above FEM analysis. Finally, a model calibrate is designed and tested to prove feasibility of present measurement method.
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Serret, Jordi, Bernardo Kahn, Bruce Cavanagh, Patricia Lorente, Remy Pascal, Clementine Girandier, Paul McEvoy, Carlos Cortés, Rubén Duran, and Alejandro Romero. "FLOTANT concept: floater design, integrated modelling & global performance." Journal of Physics: Conference Series 2257, no. 1 (April 1, 2022): 012007. http://dx.doi.org/10.1088/1742-6596/2257/1/012007.
Повний текст джерелаАнотація:
Abstract This paper presents the final design of the FLOTANT concept developed within the framework of a Cooperation Research Project funded by the European Union’s Horizon 2020 research and innovation programme. The FLOTANT concept is a hybrid concrete-plastic barge-type floating offshore substructure holding a 12MW wind turbine; buoyancy is achieved using plastic material (foam) fitted within the floater substructure. The paper describes the FLOTANT project innovations and presents the principal dimensions of the floating wind turbine system. The floating system has been developed to fulfil strict requirements at two different locations: Gran Canarias (GC) and West of Barra (WoB) sites. Therefore, two different mooring solutions including innovative elastomers to reduce peak loads are presented. The floating system’s intact and damaged static stability is checked along with the hydrostatic and hydrodynamic properties, showing the low-cost barge-type system’s feasibility. To ensure the desired behaviour of the floating system, a relevant subset of design load cases (DLCs) based on international standard requirements have been simulated checking the global performance of floater and moorings. Fully coupled hydro-servo-aero-elastic simulations have been performed to consider the wind and wave loading, the aerodynamic response of the rotor, the hydrodynamic response and structural dynamics of the turbine-floater-mooring assembly, and the control system actions. A summary of the results of the last design loop within the FLOTANT project is presented.
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Touzon, Imanol, Vincenzo Nava, Borja de Miguel, and Victor Petuya. "A Comparison of Numerical Approaches for the Design of Mooring Systems for Wave Energy Converters." Journal of Marine Science and Engineering 8, no. 7 (July 16, 2020): 523. http://dx.doi.org/10.3390/jmse8070523.
Повний текст джерелаАнотація:
This paper analyses the numerical outcome of applying three different well-known mooring design approaches to a floating wave energy converter, moored by means of four catenary lines. The approaches include: a linearized frequency domain based on a quasistatic model of the mooring lines, a time domain approach coupled with an analytic catenary model of the mooring system, and a fully coupled non-linear time domain approach, considering lines’ drag and inertia forces. Simulations have been carried out based on a set of realistic combinations of lines pretension and linear mass, subject to extreme environmental conditions. Obtained results provide realistic cost and performance indicators, presenting a comparison in terms of total mooring mass and required footprint, as well as the design line tension and structure offset. It has been found that lines’ viscous forces influence significantly the performance of the structure with high pretensions, i.e., >1.2, while there is acceptable agreement between the modelling approaches with lower pretensions. Line tensions are significantly influenced by drag and inertia forces because of the occurrence of snap loads due to the heaving of the floater. However, the frequency domain approach provides an insight towards the optimal design of the mooring system for preliminary designs.
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Park, In-Kyu, and Kyong-Moo Kim. "Conceptual Design of Deep-sea Multi-Point Mooring by using Two-Point Mooring." Journal of the Society of Naval Architects of Korea 45, no. 4 (August 31, 2008): 462–67. http://dx.doi.org/10.3744/snak.2008.45.4.462.
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Alvarez, A., and B. Mourre. "Optimum Sampling Designs for a Glider–Mooring Observing Network." Journal of Atmospheric and Oceanic Technology 29, no. 4 (April 1, 2012): 601–12. http://dx.doi.org/10.1175/jtech-d-11-00105.1.
Повний текст джерелаАнотація:
Abstract Ocean observing systems (OOSs) constituted by moorings and gliders are becoming relevant in oceanographic and climate studies. In these observing networks, the temporal variability is captured by mooring observations, while the spatial variability is obtained from gliders sampling in the surrounding area. The advent of this observing capability brings the need to find optimal procedures to sample a given ocean region with a glider in the presence of a neighboring mooring, in order to maximize the information content of the data collected by this observing network. Different criteria (e.g., A, G, or E optimality) commonly used in the geosciences to obtain an optimum design lead to different sampling strategies. The question of which criterion performs better for optimal design in the marine environment remains open. This work investigates optimal procedures to sample a given ocean region with a glider in the presence of a mooring. Specifically, observing systems simulation experiments (OSSEs) are carried out in the Ligurian Sea (western Mediterranean) in August 2010 to study the different sampling strategies. Three criteria, which respectively aim at minimizing the trace (A optimal), maximum diagonal value (G optimal), and maximum eigenvalue of the error covariance matrix (E optimal), are considered. The resulting temperature field estimations are evaluated against a control field at 50-, 100-, and 150-m depth. The results indicate that the most appropriate strategy for environmental characterization using gliders employs the A optimal criterion, minimizing the mean uncertainty over the study area.
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Youssef Mahfouz, Mohammad, Matthew Hall, and Po Wen Cheng. "A parametric study of the mooring system design parameters to reduce wake losses in a floating wind farm." Journal of Physics: Conference Series 2265, no. 4 (May 1, 2022): 042004. http://dx.doi.org/10.1088/1742-6596/2265/4/042004.
Повний текст джерелаАнотація:
Abstract Wake effects inside a conventional fixed bottom wind farm decrease the power produced by the downwind turbines, hence decreasing the farm’s annual energy production (AEP). However, floating offshore wind turbines (FOWTs) have the ability to relocate their positions laterally through surge and sway motions. This flexibility provides a new degree of freedom (DOF) in the floating wind farm layout, which can be used to decrease the aerodynamic interactions inside the floating wind farm and hence decrease the wake losses. The lateral movement of FOWTs can be passively controlled by the mooring system design. The mooring system’s restoring characteristics allows the FOWT to only move within a specific area in the x-y plane known as the watch circle. Current state of the art mooring system designs are following oil and gas design basis where the floating platforms are not allowed to have large lateral displacements. In this work, we use full factorial design to analyse the effect of different mooring system design parameters on the ability of the floater to relocate its position. The analysis shows that each design parameter has a different way of affecting the FOWT’s response. The mooring lines’ headings control which wind directions cause the biggest displacements in the crosswind direction. The smaller the lines’ diameters the higher the displacements of the FOWT. Finally, the longer the line length the smaller the mooring system’s stiffness and hence the larger the FOWT’s displacement. The results of this study can be used as the basis for floating wind farm optimization, in which the wind turbines are allowed to passively relocate their positions according to the wind speed and wind direction.
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Qiao, Dongsheng, Binbin Li, Jun Yan, Yu Qin, Haizhi Liang, and Dezhi Ning. "Transient Responses Evaluation of FPSO with Different Failure Scenarios of Mooring Lines." Journal of Marine Science and Engineering 9, no. 2 (January 20, 2021): 103. http://dx.doi.org/10.3390/jmse9020103.
Повний текст джерелаАнотація:
During the long-term service condition, the mooring line of the deep-water floating platform may fail due to various reasons, such as overloading caused by an accidental condition or performance deterioration. Therefore, the safety performance under the transient responses process should be evaluated in advance, during the design phase. A series of time-domain numerical simulations for evaluating the performance changes of a Floating Production Storage and Offloading (FPSO) with different broken modes of mooring lines was carried out. The broken conditions include the single mooring line or two mooring lines failure under ipsilateral, opposite, and adjacent sides. The resulting transient and following steady-state responses of the vessel and the mooring line tensions were analyzed, and the corresponding influence mechanism was investigated. The accidental failure of a single or two mooring lines changes the watch circle of the vessel and the tension redistribution of the remaining mooring lines. The results indicated that the failure of mooring lines mainly influences the responses of sway, surge, and yaw, and the change rule is closely related to the stiffness and symmetry of the mooring system. The simulation results could give a profound understanding of the transient-effects influence process of mooring line failure, and the suggestions are given to account for the transient effects in the design of the mooring system.
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Depalo, Francesco, Shan Wang, Sheng Xu, and C. Guedes Soares. "Design and Analysis of a Mooring System for a Wave Energy Converter." Journal of Marine Science and Engineering 9, no. 7 (July 19, 2021): 782. http://dx.doi.org/10.3390/jmse9070782.
Повний текст джерелаАнотація:
The objective of this work is to develop an efficient method to carry out the preliminary design of the mooring system for a wave energy converter. A practical mooring design procedure is applied to a specific case of study, and it can be replicated for other cases. Firstly, the static analysis is performed for a configuration with three mooring cables with different pre-tensions on fairlead, diameters of the cables, and materials. Based on these configurations from the static analysis, a quasi-static analysis is carried out in the frequency domain and a preliminary design is conducted according to DNV rules. Then, a 3-h dynamic analysis in the time domain is performed on several selected configurations, considering the same environmental conditions in the quasi-static analysis using the finite element method. Extreme dynamic responses of the system, such as extreme surge motion and mooring tensions, are estimated by the global maximum method, which is performed by fitting 20 individual maximum observations by Gumbel distribution. The quasi-static method is validated by comparing the results of extreme tension and displacement with the coupled time domain analysis. In addition, the influence of pre-tensions and cable diameters on the static and dynamic responses of the mooring system are discussed.
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Haldar, Biswajit, Abhishek Tandon, Karakunnel Jossia Joseph, Manickavasagam Arul Muthiah, Puniyamoorthy Senthilkumar, and Ramasamy Venkatesan. "Remapping of Temperature Profile Measurements in OMNI Buoy Systems." Marine Technology Society Journal 56, no. 6 (December 15, 2022): 46–57. http://dx.doi.org/10.4031/mtsj.56.6.3.
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Abstract The OMNI (Ocean Moored Buoy Network for northern Indian Ocean) buoy network comprises 12 buoy systems that measure surface meteorological parameters along with temperature and salinity profile measurements at discrete levels up to 500 m. All the OMNI buoy systems are deployed with slack-line moorings, which respond more to wind, wave, and current forcing compared to taut-line mooring. Subsurface temperature measurements are subject to change depending on both environmental condition and mooring design. The standard sensor fit of the OMNI buoy systems has only one pressure sensor fixed at 500 m, which shows significant depth variability. In order to see the spatial and seasonal variability in the vertical movement of the mooring line and the associated temperature variability, four deployments with additional pressure measurements at 200 m are analyzed. It is observed that the depth/temperature variability exhibits significant seasonality with maximum variability during pre-monsoon season. Also, the effect of this movement in the shallower depths is analyzed with four more pressure sensors in the mooring line for a 1-year period in the central Bay of Bengal. The analysis shows that the maximum value of average and root mean square (RMS) temperature deviations is 0.38 °C and 0.48 °C in the deepest interpolated depth at 400 m where the mooring line experiences a greater range of motion and the actual temperature variability in shallower depths is negligible particularly up to 75 m (<0.01°C). The study reveals the necessity of additional pressure measurements for better remapping of temperature profile measurements.
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Giannini, Gianmaria, Paulo Rosa-Santos, Victor Ramos, and Francisco Taveira-Pinto. "On the Development of an Offshore Version of the CECO Wave Energy Converter." Energies 13, no. 5 (February 26, 2020): 1036. http://dx.doi.org/10.3390/en13051036.
Повний текст джерелаАнотація:
Offshore locations present significant amounts of wave energy and free sea space, which could facilitate the deployment of larger numbers of wave energy converters (WECs) in comparison with nearshore regions. The present study aims to find a suitable design for an offshore floating version of CECO, a sloped motion WEC. For this purpose, a new design methodology is proposed in this paper for identifying and assessing possible floating configurations of CECO, which consists of four distinct set-ups obtained by varying the type of main supporting structure and the mooring system. Two options are based on spar designs and the other two on tension leg platform (TLP) designs. Based on outcomes of time-domain numerical calculations, the aforementioned configurations were assessed in terms of annual wave energy conversion and magnitude of mooring loads. Results indicate that a TLP configuration with an innovative mooring solution could increase the annual energy production by 40% with respect to the fixed version of CECO. Besides, the mooring system is found to be a key component, influencing the overall system performance.
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Lin, Mou, Yong Ma, and Liang Zhang. "Optimal Design of the Mooring System for a Floating Hybrid Ocean Renewable Power Generation System." Applied Mechanics and Materials 672-674 (October 2014): 407–12. http://dx.doi.org/10.4028/www.scientific.net/amm.672-674.407.
Повний текст джерелаАнотація:
This paper presents an optimal design model for the floating platform catenary mooring system and applies it to a floating hybrid ocean renewable power generation system. The mathematic description on the model is established based on catenary theory and static analysis method and a MATLAB toolbox is developed to get the optimized mooring system design. A numerical verification to the mooring system’s performance in AQWA is then carried out and proves the effectiveness of the presented optimization model.
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Dewey, Richard K. "Mooring Design & Dynamics—a Matlab® package for designing and analyzing oceanographic moorings." Marine Models 1, no. 1-4 (December 1999): 103–57. http://dx.doi.org/10.1016/s1369-9350(00)00002-x.
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