Book•
Hydrodynamics of Offshore Structures
01 Mar 1987-
TL;DR: In this article, the authors describe wave mechanics and how to choose wave theories and design waves, and how this wave is used to obtain forces on a fixed offshore structure, if the structure is allowed to move, various methods of obtaining the motions of the structure are given.
Abstract: The subject of hydrodynamics applied to offshore structures is vast. The topics covered in this book aim to help the reader understand basic principles while at the same time giving the designer enough information for particular designs. Thus, results are given with derivations, and applications are discussed with the aid of examples, with an overview of the advantages and limitations of the method involved. This makes the book suitable as a text for undergraduate and graduate students specializing in offshore and ocean engineering. In addition, the final results, including tables and illustrations may be referenced directly without going through detailed derivations. They can therefore be used by design and applications engineers involved in offshore structure design. This title also introduces various types of offshore structures with reference to actual installations in various parts of the world. It describes wave mechanics and how to choose wave theories and design waves. After a choice of design wave is made, the author describes how this wave is used to obtain forces on a fixed offshore structure. If the structure is allowed to move, various methods of obtaining the motions of the structure are given. The short- and long-term responses are derived and different methods are described. The use of model tests to verify these methods at each step is shown.
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TL;DR: In this paper, the authors describe the interaction between oscillations and waves, and describe the absorption of wave energy by oscillating bodies by wave-energy absorption by oscillated bodies, as well as wave interactions with oscillating water columns.
Abstract: 1. Introduction 2. Mathematical description of oscillations 3. Interaction between oscillations and waves 4. Gravity waves on water 5. Wave-body interactions 6. Wave-energy absorption by oscillating bodies 7. Wave interactions with oscillating water columns Bibliography Index.
743 citations
TL;DR: The WindFloat as discussed by the authors is a three-legged floating foundation for multimegawatt offshore wind turbines, which is designed to accommodate a wind turbine, 5 MW or larger, on one of the columns of the hull with minimal modifications to the nacelle and rotor.
Abstract: This manuscript summarizes the feasibility study conducted for the WindFloat technology. The WindFloat is a three-legged floating foundation for multimegawatt offshore wind turbines. It is designed to accommodate a wind turbine, 5 MW or larger, on one of the columns of the hull with minimal modifications to the nacelle and rotor. Potential redesign of the tower and of the turbine control software can be expected. Technologies for floating foundations for offshore wind turbines are evolving. It is agreed by most experts that the offshore wind industry will see a significant increase in activity in the near future. Fixed offshore turbines are limited in water depth to ∼30–50 m. Market transition to deeper waters is inevitable, provided that suitable technologies can be developed. Despite the increase in complexity, a floating foundation offers the following distinct advantages: Flexibility in site location; access to superior wind resources further offshore; ability to locate in coastal regions with limited shallow continental shelf; ability to locate further offshore to eliminate visual impacts; an integrated hull, without a need to redesign the transition piece between the tower and the submerged structure for every project; simplified offshore installation procedures. Anchors are significantly cheaper to install than fixed foundations and large diameter towers. This paper focuses first on the design basis for wind turbine floating foundations and explores the requirements that must be addressed by design teams in this new field. It shows that the design of the hull for a large wind turbine must draw on the synergies with oil and gas offshore platform technology, while accounting for the different design requirements and functionality of the wind turbine. This paper describes next the hydrodynamic analysis of the hull, as well as ongoing work consisting of coupling hull hydrodynamics with wind turbine aerodynamic forces. Three main approaches are presented: The numerical hydrodynamic model of the platform and its mooring system; wave tank testing of a scale model of the platform with simplified aerodynamic simulation of the wind turbine; FAST, an aeroservoelastic software package for wind turbine analysis with the ability to be coupled to the hydrodynamic model. Finally, this paper focuses on the structural engineering that was performed as part of the feasibility study conducted for qualification of the technology. Specifically, the preliminary scantling is described and the strength and fatigue analysis methodologies are explained, focusing on the following aspects: The coupling between the wind turbine and the hull and the interface between the hydrodynamic loading and the structural response.
406 citations
TL;DR: In this article, a physically consistent method is used for the reconstruction of velocity fluxes which arise from discrete equations for the mass and momentum balances, and a comparison of phase-averaged velocity vectors between measurements and predictions is presented.
298 citations
TL;DR: Very large floating structures (VLFS) have attracted the attention of architects, city planners and engineers because they provide an exciting and environmentally friendly solution for land creation from the sea as opposed to the traditional land reclamation method as mentioned in this paper.
158 citations
TL;DR: In this article, a mathematical model of liquid sloshing in rectangular tanks, which includes the effects of flow-dampening devices, is developed for the purpose of damper application.
142 citations