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"Floating"
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Does it sink or float?
\"Vibrant photographs and accessible text introduce young scientists to the concept of density. Readers are encouraged to explore what makes some objects float and others sink.\"--Provided by publisher.
Book
Wave Basin Tests of a Multi-Body Floating PV System Sheltered by a Floating Breakwater
The development of floating photovoltaic systems (FPV) for coastal and offshore locations requires a solid understanding of a design’s hydrodynamic performance through reliable methods. This study aims to extend insights into the hydrodynamic behavior of a superficial multi-body FPV system in mild and harsh wave conditions through basin tests at scale 1:10, with specific interest in the performance of hinges that interconnect the PV panels. Particular effort is put into correctly scaling the elasticity of the flexible hinges that interconnect the PV modules. Tests of a 5 × 3 FPV matrix are performed, with and without shelter, by external floating breakwater (FBW). The results show that the PV modules move horizontally in the same phase when the wave length exceeds the length of the FPV system, but shorter waves result in relative motions between modules and, for harsh seas, in hinge buckling. Relative motions suggest that axial loads are highest for the hinges that connect the center modules in the system and for normal wave incidence, while shear loads are highest on the outward hinges and for oblique incidence. The FBW reduces hinge loads as it attenuates the high-frequency wave energy that largely drives relative motions between PV modules.
Journal Article
What floats in a moat?
While trying to cross a moat, Archimedes the Goat and Skinny the Hen learn why objects sink or float.
Book
Modernization of floating dock to increase lifting capacity
Modernizing floating structures and facilities is carried out to improve certain characteristics or qualities. In the context of the maritime industry, this activity is often undertaken to increase load capacity or change the vessel’s purpose. This article examines the possibility of increasing the load capacity of a floating dock by varying its length. The key aspect here is that the modernization is performed within the conditions of a small or medium-sized ship repair enterprise (SME). The analysed floating dock is designed considering the production constraints of an SME. The modernization mustn’t alter the hull structure; instead, the study examines to what extent the existing design can withstand the loads and how much the load capacity can be increased. It has been established that the extension can be made by approximately 10.0 meters, improving the dock’s operational qualities. As a result of the extension, the lifting capacity is increased by about 12.5%, or approximately 225 tons.
Journal Article
Market Needs, Opportunities and Barriers for the Floating Wind Industry
This paper reviews the status of floating wind energy expansion, market needs, opportunities, and barriers. Even more expensive than many other generation technologies currently, the floating wind will contribute to the decarbonization of Europe. This document assesses the market strategies available to develop floating wind farms in Europe. The study includes four main phases in addition to the overview of the current state-of-the-art: a technology review, market outlook, opportunities, and commercialization barriers. During its development, the offshore wind has moved from experimentation to a final design (Semisubmersible/barge, Tension Leg Platform, and Spar).
Journal Article
Experimental and numerical study on motion instability of modular floating structures
The parametric resonance, found in a single floating body, discloses that the kinetic energy could be transferred from heave mode to roll mode and causes motion instability if there is an integer multiple relationship between the two mode natural frequencies. For multi-module floating structures, the event of parametric resonance has not been investigated, but important for the stability and safety design of the floating platforms. In this paper, an experimental test is carried out using five box-type floating modules in a wave flume and observes the existence of the parametric resonance between the heave mode and roll mode. A mathematical model, validated by the experiment data, is built up for the theoretical analysis of the influential factors of the parametric resonance. The effects on the motion instability of wave condition, connector stiffness and number of modules are analyzed. It reveals that an appropriate stiffness setting of the connectors could eliminate the parametric resonance of multi-module floating structures. This theoretical finding is confirmed in a further experiment test on a five-module floating structure in the wave flume.
Journal Article
Three-Dimensional Hydroelasticity of Multi-Connected Modular Offshore Floating Solar Photovoltaic Farm
This paper investigates the hydroelastic responses of offshore floating solar photovoltaic farms (OFPVs). OFPVs usually occupy a large sea space in the order of hectares and structural deformation under wave action has to be taken into consideration due to their huge structural length-to-thickness ratio. The flexible deformation of the structure under hydrodynamic loading is termed the hydroelastic response. In the hydroelastic analysis of an OFPV, the diffraction and radiation of waves have to be taken into account to accurately represent the hydrodynamic loadings on the floating platform. In this study, the numerical model is first validated by comparing the eigenvalues and eigenvectors of an OFPV, obtained from the proposed numerical scheme, with their counterparts obtained from an established finite element software. This is followed by an investigation of the hydroelastic responses of various OFPVs designed in varying layout configurations. The various layout configurations are obtained by altering the floating modular units’ dimensions as well as the spacing of the OFPVs when deployed adjacent to each other. The optimal configuration that gives the best performance in terms of the overall smallest response, known as compliance, is then suggested. The results suggest that a long-ish OFPV layout has a lower hydroelastic response and that the motion could be further reduced by rearranging the layout arrangement to increase the global flexural stiffness.
Journal Article
Prediction Model of Photovoltaic Module Temperature for Power Performance of Floating PVs
Rapid reduction in the price of photovoltaic (solar PV) cells and modules has resulted in a rapid increase in solar system deployments to an annual expected capacity of 200 GW by 2020. Achieving high PV cell and module efficiency is necessary for many solar manufacturers to break even. In addition, new innovative installation methods are emerging to complement the drive to lower $/W PV system price. The floating PV (FPV) solar market space has emerged as a method for utilizing the cool ambient environment of the FPV system near the water surface based on successful FPV module (FPVM) reliability studies that showed degradation rates below 0.5% p.a. with new encapsulation material. PV module temperature analysis is another critical area, governing the efficiency performance of solar cells and module. In this paper, data collected over five-minute intervals from a PV system over a year is analyzed. We use MATLAB to derived equation coefficients of predictable environmental variables to derive FPVM’s first module temperature operation models. When comparing the theoretical prediction to real field PV module operation temperature, the corresponding model errors range between 2% and 4% depending on number of equation coefficients incorporated. This study is useful in validation results of other studies that show FPV systems producing 10% more energy than other land based systems.
Journal Article
A review of modelling techniques for floating offshore wind turbines
Modelling floating offshore wind turbines (FOWTs) is challenging due to the strong coupling between the aerodynamics of the turbine and the hydrodynamics of the floating platform. Physical testing at scale is faced with the additional challenge of the scaling mismatch between Froude number and Reynolds number due to working in the two fluid domains, air and water. In the drive for cost‐reduction of floating wind energy, designers may be seeking to move towards high‐fidelity numerical modelling as a substitute for physical testing. However, the numerical engineering tools typically used for FOWT modelling are considered as mid‐fidelity to low‐fidelity tools, and currently lack the level of accuracy required to do so. Furthermore, there is a lack of operational FOWT data available for further development and validation. High‐fidelity tools, such as CFD, have greater accuracy but are cumbersome tools and still require validation. Physical scale model testing therefore continues to play an essential role in the development of FOWTs both as a source of validation data for numerical models and as an important development step along the path to commercialization of all platform concepts. The aim of this paper is to provide an overview of both numerical modelling and physical FOWT scale model testing approaches and to provide guidance on the selection of the most appropriate approach (or combination of approaches). The current state‐of‐the‐art will be discussed along with current research trends and areas for further investigation.
Journal Article
Motion response analysis of multi-module hinged floating structures based on CFD-FEA method
The motion responses for a hinged floating structure are usually difficult to model due to the complex turbulence phenomenon. A systematic analysis of the motions of the multi-module hinged floating bridge in different wave conditions was carried out using the method. The RANS and VOF techniques captured the turbulence phenomenon very well. Through conducting a co-simulation with the multi-module hinged floating structure, it was verified that the developed coupling method can accurately simulate almost all physical characteristics in the range of the floating structure’s motions under wave loading. The numerical CFD-FEA method proposed in this paper exhibited an obvious advantage over the traditional analysis methods.
Journal Article