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Your search keyword '"Greaves, Deborah"' showing total 160 results
Start Over Author "Greaves, Deborah" Publication Type Academic Journals
160 results on '"Greaves, Deborah"'

20. Dual-purpose wave farm with nonlinear stiffness mechanism for energy extraction and wave attenuation.

Author

Jin, Huaqing, Zhang, Haicheng, Zheng, Siming, Lu, Ye, Xu, Daolin, and Greaves, Deborah

Subjects
COMPUTATIONAL fluid dynamics, OCEAN wave power, AGRICULTURAL exhibitions, SHORE protection, NONLINEAR waves
Abstract

This study proposes a novel model of a dual-purpose nonlinear wave farm, wherein multiple wave energy converters (WECs) equipped with nonlinear stiffness mechanism (NSM) are deployed for energy production and wave attenuation. A hybrid semi-analytical approach integrating the eigenfunction expansion matching method (EEMM) with the multi-harmonic balance method (MHBM) is developed to address the nonlinear wave-structure interactions among an array of WECs. Each device is modeled as a truncated cylinder, and the effects of the nonlinear interaction on power absorption and wave evolution from the array are studied. The analytical results are validated through published experimental results and computational fluid dynamics (CFD) results. A multi-parameter analysis is conducted to explore the impact of various factors including power takeoff (PTO) damping, NSM configuration, wave direction, and layout geometry on both wave power absorption and wave evolution. The results demonstrate that the nonlinear wave farm exhibits improved power-capture efficiency and enhanced wave attenuation compared to the linear wave farm, attributed to the phase control mechanism of NSM. This work may provide profound guidelines for large-scale wave energy exploitation and coast protection. [ABSTRACT FROM AUTHOR]

Published
2024
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39. A Jacket-Frame Mounted Oscillating Water Column with a Variable Aperture Skirt.

Author

Pérez-Collazo, Carlos, Greaves, Deborah M., and Iglesias, Gregorio

Subjects
WIND waves, OFFSHORE wind power plants, WIND power, WAVE energy, SKIRTS
Abstract

During the last decade jacket-frames have emerged as the main kind of substructure for bottom-mounted offshore wind farms in intermediate water depths. With the offshore wind industry moving towards deeper waters, the predominance of jacket-frames is expected to increase in future years. Multipurpose platforms combining wind and wave energy are proposed as an innovative solution to enhance the sustainability of offshore wind energy. In this research, a multipurpose platform is investigated with a novel feature in its oscillating water column (OWC) wave energy converter—a variable geometry skirt. A comprehensive physical modelling campaign was carried out using a 1:50 scale model. The performance of the OWC and its interaction with the wave field were investigated under four different skirt aperture angles. It was found that the skirt aperture angle plays a significant role in the capture-width ratio and the pneumatic mean power of the OWC. The best performance was obtained with a skirt aperture angle of 140 deg. More generally, these results prove that the variable-geometry skirt is a promising innovation for hybrid wave-wind systems mounted on jacket-frame substructures. [ABSTRACT FROM AUTHOR]

Published
2023
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49. Wave diffraction and radiation from a semi-submersible floating foundation for wind turbines: A semi-analytical study.

Author

Zhu, Kai, Zheng, Siming, Michele, Simone, Cao, Feifei, Shi, Hongda, and Greaves, Deborah

Subjects
WIND turbines, EIGENFUNCTION expansions, EQUATIONS of motion, POTENTIAL flow, BASES (Architecture), WAVE diffraction, OFFSHORE structures
Abstract

Many marine structures are composed of vertical axisymmetric floats. In this paper, a semi-analytical model based on the linear potential flow theory and an eigenfunction expansion method is developed to study wave diffraction and radiation by an array of cylindrical structures. Each structure can be formed by three coaxial cylinders of different dimensions. Based on the semi-analytical model, a constrained matrix equation of motion is presented and solved to evaluate the performance of multiple interconnected cylindrical structures. In order to verify the accuracy of the semi-analytical model, a typical OC4-DeepCwind floating offshore wind turbine (FOWT) is selected for validation. The validated model is, then, applied to study the effect of base column submergence depth, radius, and thickness on the motion response of a semi-submersible platform. Although the results of this study are of significance for the selection of the optimum semi-submersible FOWT for specific locations (with specific prevailing wave directions), the focus of this work was placed on the semi-analytical model itself, which is efficient in modeling the interaction of the wave field and can be used in future FOWT projects. [ABSTRACT FROM AUTHOR]

Published
2023
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