• 한국지진공학회논문집
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• 제19권4호
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• pp.145-159
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• 2015

A seismic response analysis method for three-dimensional floating offshore structures due to seaquakes is developed. The hydrodynamic pressure exerted on the structure is calculated taking into account the compressibility of the sea water, the fluid-structure interaction, the energy absorption by the seabed, and the energy radiation into infinity. To validate developed method, the hydrodynamic pressure induced by the vibration of a floating massless rigid circular disk is calculated and compared with an exact analytical solution. The developed method is applied to seismic analysis of a support structure for a floating offshore wind turbine subjected to the hydrodynamic pressures induced from a seaquake. Analysis results show that earthquake response of a floating offshore structure can be greatly influenced by the compressibility of fluid, the depth (natural frequencies) of the fluid domain, and the energy absorption capacity of the seabed.

• 대한조선학회논문집
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• 제50권6호
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• pp.373-382
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• 2013

The weight of floating offshore plant, such as an FPSO(Floating, Production, Storage, and Off-loading unit) and an offshore wind turbine, is important for estimating the amount of production material and for determining the production method. Furthermore, the weight is a factor which affects in the building cost and production time of the floating offshore plant. Although the importance of the weight has long been recognized, the weight has been roughly estimated by using the existing design and production data, and designer's experience. To solve this problem, a simplified model for the weight estimation of the floating offshore plant using the statistical method was proposed in this study. To do this, various data for estimating the weight of the floating offshore plant were collected through the literature survey, and then the correlation analysis and the multiple regression analysis were performed to generate the simplified model for the weight estimation. Finally, to examine the applicability of the developed model, it was applied to examples of the weight estimation of an FPSO topsides and an offshore wind turbine. As a result, it was shown that the developed model can be applied the weight estimation process of the floating offshore plant at the early design stage.

• 한국해양공학회지
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• 제25권5호
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• pp.64-68
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• 2011

The motion responses of a 5-MW floating offshore wind turbine were simulated in regular and irregular waves and its RAOs and significant motion responses were calculated, respectively. The floating offshore wind turbine employed in this simulation was the OC3-Hywind designed by the National Renewable Research Laboratory, USA. The numerical simulation was carried out using MOSES (Multi-Operational Structural Engineering Simulator), which is widely used to analyze and design floating offshore structures in the gas and oil industry.

• 한국CDE학회논문집
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• 제18권6호
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• pp.439-450
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• 2013

In the case of a floating offshore structure such as FPSO(Floating, Production, Storage, and Offloading unit), many equipment should be installed in the limited space, as compared with an onshore structure. Recently, the requirement for an optimal layout method of the structure has been raised. Thus, a layout method of the floating offshore structure was proposed in this study. First, an optimization problem for layout design was mathematically formulated, and then an optimization algorithm was implemented based on the genetic algorithm in order to solve it. To evaluate the applicability of the proposed method, it was applied to examples ofFPSO topsides and an offshore wind turbine. As a result, it was shown that the proposed method can be applied to layout design of the floating offshore structure.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.614-622
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• 2011

In this study, the computational structural dynamic modeling of floating offshore wind turbine system is presented using efficient equivalent modeling technique. Structural dynamic behaviors of the offshore floating platform with 5MW wind turbine system have been analyzed using computational multi-body dynamics based on the finite element method. The considered platform configuration of the present offshore wind turbine model is the typical spar-buoy type. Equivalent stiffness and damping properties of the floating platform were extracted from the results of the baseline model. Dynamic responses for the floating wind turbine models are presented and compared to investigate its structural dynamic characteristics. It is important shown that the results of the present equivalent modeling technique show good and reasonable agreements with those by the fully coupled analysis considering complex floating body dynamics.

• Wind and Structures
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• 제24권4호
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• pp.333-350
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• 2017

Differing from the fixed-type, the dynamic motion of floating-type offshore wind turbines is very sensitive to wind and wave excitations. Thus, the sensing and monitoring of its motion is important to evaluate the dynamic responses to the external excitation. In this context, a monitoring system for sensing and processing the wind-induced dynamic motion of spar-type floating offshore wind turbine is developed in this study. It is developed by integrating a 1/00 scale model of 2.5MW spar-type floating offshore wind turbine, water basin equipped with the wind generator, sensing and data acquisition systems, real-time CompactRIO controller and monitoring program. The scale model with the upper rotatable blades is installed within the basin by means of three mooring lines, and its translational and rotational motions are detected by 3-axis inclinometer and accelerometers and gyroscope. The detected motion signals are processed using a real-time controller CompactRIO to calculate the acceleration and tilting angle of nacelle and the attitude of floating platform. The developed monitoring system is demonstrated and validated by measuring and evaluating the time histories and trajectories of nacelle and platform motions for three different wind velocities and for eight different fairlead positions.

• 대한조선학회논문집
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• 제52권1호
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• pp.77-87
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• 2015

For a floating offshore plant such as FPSO(Floating, Production, Storage, and Off-loading unit), various equipment should be installed in the restricted space, as compared with an onshore plant. The requirement for an optimal layout method of the plant has been increased in these days. Thus, a layout method of the floating offshore plant was proposed in this study. For this, an optimization problem for layout design was mathematically formulated, and then an optimization algorithm based on the genetic algorithm was implemented with C++ language in order to solve it. Finally, the proposed method was applied to an example of FPSO topsides. As a result, it was shown that the proposed method can be applied to layout design of the floating offshore plant such as FPSO.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.466-472
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• 2009

Offshore wind energy is gaining more and more attention during this decade. For the countries with coast sites, the water depth is significantly large. This causes attention to the floating wind turbine. Offshore wind turbines are designed and analyzed using comprehensive simulation codes that account for the coupled dynamics of the wind inflow, aerodynamics, elasticity and controls of the wind turbine, along with the incident waves, sea current, hydrodynamics, and foundation dynamics of the support structures. In this work, a three-bladed 5MW upwind wind turbine installed on a floating spar buoy in 320m of water is studied by using of fully coupled aero-hydro-servo-elastic simulation tool. Specifications of the structures are chosen from the OC3 (Offshore Code Comparison Collaboration) under "IEA Wind Annex XXIII-subtask2". The primary external conditions due to wind and waves are simulated. Certain design load case is investigated.

• 신재생에너지
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• 제20권1호
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• pp.38-51
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• 2024

The rapid expansion of industrialization and population growth worldwide has led to a significant surge in energy demand, perpetuating heavy reliance on finite fossil fuel reserves. Although prevailing policies primarily target ground-mounted solar photovoltaics, there is a noticeable increase in the adoption of floating solar power generation systems on water surfaces. Nonetheless, adequate studies and legislative reviews on offshore solar photovoltaics in Korea are lacking. The absence of well-defined criteria for the economic analysis of floating solar photovoltaics presents hurdles to their economic feasibility. This study conducted a comprehensive cost-benefit analysis of offshore photovoltaics to evaluate their economic viability and compared four types of solar photovoltaics based on the operating area and technology: ground-mounted, floating on inland water, pontoon-based offshore, and flexible system offshore. Perspectives from both central and local government entities, emphasizing social aspects, as well as inputs from private companies with a financial focus were considered. The findings revealed variations in economic viability depending on the operating area and technology employed. This study aims to contribute to the advancement of market maturity and technology within the realm of offshore solar photovoltaics.

• 풍력에너지저널
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• 제14권2호
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• pp.14-25
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• 2023

This study focuses on proposing measures for the reasonable development of offshore wind farms using the case of Norway, which was the first nation in the world to build a floating offshore wind farm of 80 MW or more. Norwegian authorities conducted a strategic environment assessment in 2012 to select offshore wind farm sites, discovered 15 potential sites, and finally decided on two designated sites in 2020. Based on various survey data such as seabirds, marine environment, and fishing activities, scientific-based spatial analysis was conducted to select additional offshore wind farm sites in line with future development plans. In addition, a government-led steering committee and advisory group have established marine spatial plans since 2002. Therefore, it will be possible to listen to and coordinate the opinions of stakeholders by using the steering committee and advisory group for offshore wind power development. By examining the case of Norway, we suggest the following policy points that can achieve carbon neutrality and develop sustainable offshore wind farms: 1. Establish a government-led steering committee and advisory group that can select potential sites for offshore wind farms by coordinating the opinions of stakeholders 2. Induce efficient and sequential offshore wind farm development by using various survey data and scientific-based spatial analysis.