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The vast and advantages of offshore wind resources continuously motivate the development of offshore floating wind turbines. This paper describes a model and proceeds preliminary design of a 60 meter deep offshore Tension Leg Platform (TLP) floating foundation for the NREL 5 MW prototype wind turbine and analysis the reliability of the wind turbine...
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... and cheaper than floating foundation. However research 4 shows that in water more than 60 meters depth, the floating wind turbine foundation should be used because the construction cost will decrease. The foundation design and construction is considered to be one of the main factors caused the high cost of offshore wind power 4 as shown in Fig. 1. Thus, to develop more economical floating offshore wind turbine is necessary to make offshore wind energy a significant contributor to the total energy market within the U.S. However sea environment is more complex as the water goes deeper because floating movement has the relationship with sea-based wind, wave loads, current loads ...
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In order to explore a set of methods to analyze the structure of Lift-Drag Combined-Type Vertical Axis Wind Turbine (LD-VAWT), a small LD-VAWT was designed according to the corresponding Standards and General Design Requirements for small vertical axis wind turbines. The finite element method was used to calculate and analyze the static mechanical...
Citations
... (OWE, 2009). Compared to its onshore counterparts, offshore wind can be 1.2-2 times faster and electricity production can be 1.7 times more powerful, and energy efficiency generally increases by going further from land (Kaldellis et al., 2016;Li et al., 2014). Offshore wind development has had a really interesting growth since the first large commercial wind farm was installed in Vindeby, Denmark in 1991 (Orsted, 2021;Rodrigues et al., 2015). ...
Colombia has a renewable installed capacity of close to 70% in hydroelectric generation. However, especially in dry periods, thermal generation (mostly based on natural gas) has played a dominant role in the country's generation. In this sense, thermal generation has considerably increased greenhouse gas (GHG) emissions, added to the fact that the proven reserves of natural gas are projected to a few years of supply, which makes its use unfeasible in the long term. Under this context, this work proposes to analyze the wind potential and complementarity with hydraulic generation in Colombia, from a climatological approach. The above, with the objective of determining if wind can be a viable alternative to guarantee the firmness of energy generation, reducing the dependence on non-renewable energies. For this purpose, wind atlases, data from hydrometeorological stations, reanalysis, satellite data, and climate change models are used. Based on this, the wind complementarity with basins for energy generation of the Sistema Interconectado Nacional (SIN) is established in regional terms and the places with the greatest wind potential in the country are determined. Subsequently, the offshore wind potential is studied in scenarios of climate variability and climate change. The results of this research indicate that there is a wide hydro-wind complementarity between different regions. It is worth highlighting the seasonal and interannual complementarity associated with ENSO of the most important hydroelectric region, with multiple regions of high wind potential such as the Caribbean Sea, among others. It was also determined, a higher net generation of wind farms in a location in the sea of La Alta Guajira in relation to equal installed capacities of important hydroelectric plants. This location also had a higher generation relative to the offshore potential of Buchan Deep in the North Sea. It was found that the migration phenology of migratory birds in the Caribbean coincides with the minimum offshore wind generation within the seasonal scale. Finally, multi-annual climate change projections predict that the offshore wind resource in the highest potential locations will remain stable or increase slightly. They also show for this century a likely seasonal compensation between reductions in precipitation in the Andes with increases in offshore wind potential in the Colombian Caribbean Sea and vice versa.
... First, offshore wind allows for development in populous regions where there is little land available, but the local energy demand is high. Offshore wind turbines can also be larger, by removing restrictions on transporting turbine components by road [14]. These offshore turbines reduce visual and noise impacts of wind farms, and may reduce local opposition to development of wind farms. ...
Choosing a proper location is a pivotal initial step in building a wind farm. As appropriate locations for onshore wind farms become more and more scarce, offshore wind farms have drawn significant attention. The coastal line of the Great Lakes is an area that has great wind energy potential. This research conducted detailed statistical analysis of the onshore, nearshore, and offshore wind energy potential of Lake Erie near Cleveland, Ohio. It analyzed the wind data collected in 10-min time intervals from three locations near the Lake Erie shoreline to assess wind characteristics. Statistical analyses of wind data include the Weibull shape and scale factors, turbulence intensity, and wind power density. In addition, the capacity factor and the potential energy output are estimated by using two commercial wind turbines, which are appropriate for the sites at 50 m and 80 m hub heights. The results show that offshore sites will produce at least 1.7 times more energy than the onshore and nearshore sites when using the same commercial wind turbine. Furthermore, offshore wind turbines could produce more power during peak hours in the spring and winter. This indicates that offshore wind turbines offer advantages over onshore wind turbines in Lake Erie.
... Offshore wind energy shows a better resource potential: the wind speed is faster and steadier in the open sea areas, which can exceed 10 m/s at a height of 50 m [14,15]. Comparing to onshore counterparts, the offshore wind can be 1.2-2 times faster and the electrical output will be 1.7 times more powerful, and the energy yield will be generally increases by going further from land [16,17]. ...
... The floating foundation is consist of a floating platform and an anchor system connecting to the seabed [68,101]. Spar floater, tension leg platform and semi-submersible foundation are main types of offshore floating foundations, and these are based on the oil and gas industry [17,102]. The floating foundation is mainly used at a much deeper water depth that is greater than 50 m; but in the offshore wind industry, the largest water depth is about 100 m due to its characteristic [68]. ...
... The transportation of OWT is different from other offshore structures since the OWT has relatively large distance between the buoyancy center and the gravity center [17,165]. Usually, the foundation and the upper structure are transported separately. ...
The sustainable development of offshore wind energy requires thorough investigations on technological issues. The substructure, which acts as the natural link between technologies and environments, is a critical topic for the offshore wind industry. This paper presents a comprehensive review of variable types of offshore wind substructures associate with their corresponding example projects. The study is complemented with a special attention to a novel foundation, namely suction bucket foundation. Main technological issues related to this concept are integrated. In the paper, bearing behaviors of offshore wind turbines (OWTs) with the suction bucket foundation under lateral loads, vertical loads, combined loads, and extreme loading conditions are discussed. Two installation methods are introduced. The geometric and improved design is illustrated by considering capabilities in transportation and installation. Research methods, including field tests, laboratory tests, centrifuge tests, theoretical analysis and numerical simulations, are listed; these methods are employed in previous studies to investigate behaviors of the OWT. This review integrates most relevant aspects and recent advancements together, which aims to provide a reference frame for future studies and projects.
... There are several types of substructures for offshore wind turbines, and they are selected according to water depths, geotechnical conditions and wind turbine capacity (Arany et al., 2017;Sun et al., 2012). The technique for offshore wind foundation experiences rapid developments; besides the fixed foundation types, the floating foundation for offshore wind turbines has been proposed to adapt to more severe environmental or seabed conditions (Castro-Santos and Diaz-Casas, 2015;Li et al., 2014). The most widely applied foundation concept for offshore wind industry is the monopile foundation. ...
The hybrid monopile-friction wheel foundation is an innovative alternative for offshore wind turbines. The concept has wider adaptability and can be used as reinforcement method for existing monopiles. A series of centrifuge tests was performed to investigate the lateral bearing capacities of the hybrid foundation under monotonic loads. Five foundation models and two soil types were considered. According to the recorded responses, the hybrid foundation demonstrated better lateral behaviors that both lateral bearing capacity and stiffness are enhanced. Two analytical methods were proposed and compared with the centrifuge test results. The bearing capacity of the hybrid foundation is smaller than the sum of individual pile and friction wheel, and a reduction factor is suggested for both friction wheels. The friction wheel restrains rotations of monopile and provides extra restoring moments; their effects are idealized as equivalent moments acting on the pile head. The analytical results provide possible solutions in estimating the lateral bearing capacity of the innovative hybrid foundation system for offshore wind turbines by using traditional theories.
... Although the onshore wind turbines are relatively easy to construct and install, the wind source at offshore areas has the advantage of less turbulence, and would not cause visual or auditory disturbances. (Li et al., 2014;Musial and Butterfield, 2004). Because of these advantages, a number of offshore wind farms were built in the past 25 years all around the world. ...
The purpose of this paper is to evaluate the improved suction bucket foundation (ISBF) for the offshore wind turbine. The ISBF included the design of two types of internal compartments inside buckets with different aspect ratios (AP). A series of centrifuge tests were performed to investigate the lateral bearing behavior of ISBF in four types of sandy soils. Both static and cyclic lateral loads were applied by an electrical actuator in a load-controlled system. The first method interpolated the lateral bearing capacity from the load-displacement curve and reinforced the results with the stiffness-displacement relationship. Moreover, displacement rate was calculated and plotted to obtain the lateral critical and ultimate bearing capacity as the second method. During cyclic tests, the first several cycles changed the lateral displacement and stiffness significantly, whereas the last several cycles did not obviously affect them. It was demonstrated that the geometric designs of ISBF had limited influence on its lateral bearing behavior, but the soil conditions of the foundation did bring about an obvious difference. The lateral capacity of ISBF was further compared to original suction bucket foundation (OSBF), thereby illustrating the advantages of the ISBF in offshore wind turbine constructions.
... The dynamic response of the spar platform in short-crested waves revealed that short-crested waves are 35 % lesser than the long-crested in all activated degree of freedom. Li et al. [9] modelled tension leg platform for offshore wind turbine in MOSES software, and different working conditions in wave, wind and current loads are simulated for the floating structure. Gu et al. [10] simulated random wave by JONSWAP, and wind fluctuating portion is also simulated with Norwegian Petroleum Directorate (NPD) spectrum. ...
This work analysed the dynamic response of intact and a removed tendon tension leg platform (TLP) in simultaneous action of random wave and current loads in normal and less severe environments. Two different sea states of extreme severe sea state but less probable and less severe state and most probable are considered in this study. The artificial random wave is simulated by Monte Carlo simulation using Pierson–Moskowitz spectrum. Wave diffraction effect is not considered since the ratio of characteristic dimension to wavelength is less than limit. The coupling in all degree of freedoms and various degrees of nonlinear effects is considered. The inertia, mass, damping matrices of equation of motion and hydrodynamic force vector are formulated and solved numerically using Newmark integration scheme. The statistical results show that removal of one tendon increases surge and tendon tension values, while heave and pitch are not adversely affected in both environments. The response values of the TLP in extreme severe sea state are quite higher compared to less severe sea state. The percentage increase in all degree of freedoms and tendon tension is <5 % when one tendon is removed as compared to intact tendon TLP. It could be concluded that maximum and minimum tension in tendon constraints is equally passed by the TLP tendons.
Child quadriceps muscle injuries are common in contact sports such as football and
basketball. The rectus femoris muscle component of the quadriceps muscle ıs frequently
ınjured, while vastus lateralis component of quadriceps muscle is rarely injured. In this case report, we aimed to draw attention to children's sports and the rare vastus lateralis muscle rupture. In this case, we detected the 13 years old football player with isolated vastus lateralis tendon rupture. After, We successfully treated this child with activity modification, physical therapy rehabilitation and exercises.
In our country, activities are carried out under the title of zoning studies in order to make an area suitable for
holistic living standards. There is a hierarchy in the formation of zoning plans from the upper scale of the country
development plans to the lower scale, which are the implementation zoning plans. With this hierarchy, in the
1/1000 zoning plans, social cultural areas are determined within the zoning boundaries determined to meet the
social activity needs of the people living in a region. Socio-cultural zoning islands can have different building
regulations, precedent or building heights. There are possible building regulations within the zoning boundaries,
where there may be different types of sitting areas, such as split, block and adjacent basis. The process of granting
construction permits to the existing zoning parcels in the zoning islands, whose identities are determined by these
building regulations, is the zoning scale. Zoning diameters, planned areas are given within the framework of type
zoning regulations and plan notes. The zoning diameter is given according to the precedent, height and building
order of the island. Distance method, on the other hand, is the process of creating the right residential area with
the drawing rules of convex shapes, such as square or rectangular, according to the geometric condition of the
parcel, in order to be able to give construction permits to the clean zoning parcels in the relevant zoning islands.
In our study, it has been tried to show how the settlement areas on the floor can be given, which building order,
which precedent and how to apply the process to the convex parcels with the distance approach.
This paper puts forward a new method to measure the force characteristics of the buttress’ ship–pipe connection. First, the positions of stress sensors are determined by the numerical model, and the stress values at these positions are derived alongside a stress equation for the buttress. Then, the vertical stress values of the buttresses are obtained by using the established model; the results are in good agreement with the known external load. Considering the unevenness of the surface between the buttress and immersed tube, a horizontal stress equation for the whole buttress is put forward based on stress difference.Through analysis of data obtained from a real engineering project, it can be concluded that the vertical force on the buttresses fluctuates while the catamaran is floating, but within an acceptable range. The results can be used to guide future engineering projects.
انرژي باد یکی از انرژيهاي تجدید پذیر است که هم در دریا و هم در خشکی قابل بهرهبرداري میباشد. براي رساندن
بهرهبرداري بهینهتر ازاین انرژي در دریا به صورت توسعه پایدار نیاز به پیشرفت بیشتر و سرمایهگذاري گستردهتر میباشد.
دلایلی چون تمایل جهان به استفاده از این انرژي تجدیدپذیر، انتقال این صنعت به دریا و قرار داشتن مناطق دریایی گسترده در
شمال و جنوب کشور، لزوم به مطالعه و سرمایهگذاري وسیعتردر این حوزه، بیش از پیش مورد اهمیت واقع میشود. در این
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