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Full-Text Articles in Engineering
Wind-Wave Misalignment Effects On Multiline Anchor Systems For Floating Offshore Wind Turbines, Doron T. Rose
Wind-Wave Misalignment Effects On Multiline Anchor Systems For Floating Offshore Wind Turbines, Doron T. Rose
Masters Theses
Multiline anchors are a novel way to reduce the cost of arrays of floating offshore wind turbines (FOWTs), but their behavior is not yet fully understood. Through metocean characterization and dynamic simulations, this thesis investigates the effects of wind-wave misalignment on multiline anchor systems. Four coastal U.S. sites are characterized in order to develop IEC design load cases (DLCs) and analyze real-world misaligned conditions. Stonewall Bank, Oregon showed the highest 500-year extreme wave height, at 16.6 m, while Virginia Beach, Virginia showed the highest 500-year wind speed, at 56.8 m/s. Misalignment probability distributions, at all sites, are found to converge …
A Multiline Anchor Concept For Floating Offshore Wind Turbines, Casey Fontana
A Multiline Anchor Concept For Floating Offshore Wind Turbines, Casey Fontana
Doctoral Dissertations
Floating offshore wind turbines (FOWTs) hold great potential for the renewable energy industry, but capital costs remain high. In efforts to increase FOWT substructure efficiency and reduce costs, this thesis investigates a novel multiline anchor concept in which FOWTs share anchors instead of being moored separately. The goal of this thesis is to evaluate the force dynamics, design, and potential cost reduction of the system. Anchor forces are simulated using the NREL 5 MW reference turbine and OC4-DeepCwind semisubmersible platform, and multiline anchor force is computed as the vector sum of the contributing mooring line tensions. The use of a …
Bio-Based Wind Turbine Blades: Renewable Energy Meets Sustainable Materials For Clean, Green Power, Rachel Koh
Bio-Based Wind Turbine Blades: Renewable Energy Meets Sustainable Materials For Clean, Green Power, Rachel Koh
Doctoral Dissertations
Wood, once the material of choice for wind turbine blades, was phased out in the late 20th century as the growing size of blades imposed stricter material requirements and glass- and carbon-fiber composites gained industry popularity. However, the last several years have seen great advances in bio-based composite materials technology, including flax, hemp, and wood composites and laminates. These materials are increasingly utilized in high-performance, structurally demanding applications, largely because they are a more sustainable choice than many other engineering materials. Today, as the first glass-fiber wind turbine blades are ready to retire, wind developers are presented with an enormous …
Automatic Development And Adaptation Of Concise Nonlinear Models For System Identification, William G. La Cava
Automatic Development And Adaptation Of Concise Nonlinear Models For System Identification, William G. La Cava
Doctoral Dissertations
Mathematical descriptions of natural and man-made processes are the bedrock of science, used by humans to understand, estimate, predict and control the natural and built world around them. The goal of system identification is to enable the inference of mathematical descriptions of the true behavior and dynamics of processes from their measured observations. The crux of this task is the identification of the dynamic model form (topology) in addition to its parameters. Model structures must be concise to offer insight to the user about the process in question. To that end, this dissertation proposes three methods to improve the ability …
Wind Farm Wake Modeling And Analysis Of Wake Impacts In A Wind Farm, Yujia Hao
Wind Farm Wake Modeling And Analysis Of Wake Impacts In A Wind Farm, Yujia Hao
Doctoral Dissertations
More and more wind turbines have been grouped in the same location during the last decades to take the advantage of profitable wind resources and reduced maintenance cost. However wind turbines located in a wind farm are subject to a wind field that is substantially modified compared to the ambient wind field due to wake effects. The wake results in a reduced power production, increased load variation on the waked turbine, and reduced wake farm efficiency. Therefore the wake has long been an important concern for the wind farm installation, maintenance, and control. Thus a wake simulation tool is required. …
New Generator Control Algorithms For Smart-Bladed Wind Turbines To Improve Power Capture In Below Rated Conditions, Bryce B. Aquino
New Generator Control Algorithms For Smart-Bladed Wind Turbines To Improve Power Capture In Below Rated Conditions, Bryce B. Aquino
Masters Theses
With wind turbines growing in size, operation and maintenance has become a more important area of research with the goal of making wind energy more profitable. Wind turbine blades are subjected to intense fluctuating loads that can cause significant damage over time. The need for advanced methods of alleviating blade loads to extend the lifespan of wind turbines has become more important as worldwide initiatives have called for a push in renewable energy. An area of research whose goal is to reduce the fatigue damage is smart rotor control. Smart bladed wind turbines have the ability to sense aerodynamic loads …
The Aerodynamics And Near Wake Of An Offshore Floating Horizontal Axis Wind Turbine, Thomas Sebastian
The Aerodynamics And Near Wake Of An Offshore Floating Horizontal Axis Wind Turbine, Thomas Sebastian
Open Access Dissertations
Offshore floating wind turbines represent the future of wind energy. However, significant challenges must be overcome before these systems can be widely used. Because of the dynamics of offshore floating wind turbines -- surge, sway, heave, roll, pitch, and yaw -- and the resulting interactions between the rotor and generated wake, the aerodynamic analysis methods and design codes that have found wide use throughout the wind energy industry may be inadequate. Application of these techniques to offshore floating wind turbine aerodynamics may result in off-optimal designs, effectively handicapping these next-generation systems, thereby minimizing their full potential. This dissertation will demonstrate …
Advanced Blade Testing Methods For Wind Turbines, Puneet Malhotra
Advanced Blade Testing Methods For Wind Turbines, Puneet Malhotra
Masters Theses 1911 - February 2014
This thesis consists of a detailed analysis of different blade testing methods and improvements to a novel concept for tri-axial testing of large wind turbine blades. As the blades are one of the most critical components of the wind turbine, they have to be tested in order to ensure that their specifications are consistent with the actual performance of the blade. It must be demonstrated that the blade can withstand both the ultimate loads and the fatigue loads to which the blade is expected to be subjected during its design service life. There are basically two types of blade testing: …