Coupled CFD-MBD numerical modeling of a mechanically coupled WEC array

Li, Xiang; Xiao, Qing; Zhou, Yang; Ning, Dezhi; Incecik, Atilla; Nicoll, Ryan S.; McDonald, Anthony D.; Campbell, David

doi:10.1016/j.oceaneng.2022.111541

Cited by 20 publications

(6 citation statements)

References 26 publications

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“…In this problem, the WEC was made up of four floats with rigid connections in between. The incident waves came from the left side (see Figure 6a), having a wave height of 1.5 m and a wave period between 9.5 s and 10.5 s. The CFD modeling results, in terms of pitch motion responses, were in very In the second case, a conventional rigid WEC was examined in our previous study, in which the numerical modeling of a wave-structure interaction problem was very well validated against the results from wave tank testing [3]. In this problem, the WEC was made up of four floats with rigid connections in between.…”

Section: Grid and Time Step Sensitivity Study And Numerical Methods V...mentioning

confidence: 97%

“…In the second case, a conventional rigid WEC was examined in our previous study, in which the numerical modeling of a wave-structure interaction problem was very well validated against the results from wave tank testing [3]. In this problem, the WEC was made up of four floats with rigid connections in between.…”

Section: Grid and Time Step Sensitivity Study And Numerical Methods V...mentioning

confidence: 99%

“…This may be due to several inherent challenges associated with traditional WECs. One such challenge stems from the issue that many WECs are mechanically complex through the use of multiple subcomponents (e.g., the Albatern 12S Squid WEC) [3]. These structures significantly reduce the durability and stability of the WEC while also increasing manufacturing and 2 of 25 maintenance costs.…”

Section: Introductionmentioning

confidence: 99%

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A Numerical Study on an Oscillating Water Column Wave Energy Converter with Hyper-Elastic Material

Xiao

2022

Energies

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A model different from the traditional WEC, known as the flexible wave energy converter (fWEC), is numerically modeled in this paper. The fWEC is believed to be more efficient and has a greater range of operation when compared with the conventionally rigid WEC. A fully coupled fluid–structure interaction (FSI) tool is developed for the research performed in this paper. This tool is able to accommodate the dynamic interaction between the flexible membrane structure of the fWEC and the surrounding fluid. In this research, both linear-elastic and hyper-elastic materials are examined for their use in the fWEC. The fluid flow surrounding the fWEC is solved by a computational fluid dynamics (CFD) method. The deformation of the hyper-elastic structure within the fWEC is modeled using a finite element analysis method (FEA). Both the hyper-elastic material of the fWEC and the free surface wave contribute to the overall nonlinearity of the numerical simulation. To tackle this problem, a robust coupling scheme is implemented by an advanced coupling library. With this tool, the flexible deformations within the fWEC structure can be accurately captured. The degree of these deformations can then further be examined, allowing the overall effects on the fWEC energy output to be determined. The simulation results show that the peak deformation of the hyper-elastic material is four times that of the linear-elastic material. This suggests that the fWEC would perform better and generate greater power using the hyper-elastic material compared with the linear-elastic material. Additionally, because a wide range of wave conditions are studied, it can be concluded that unlike conventional WECs, the efficiency of energy harvesting of such an fWEC is not sensitive to certain wave periods. Such findings are supported by both the detailed flow fields captured and the structural stress–strain analysis results from this simulation.

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Section: Grid and Time Step Sensitivity Study And Numerical Methods V...mentioning

confidence: 97%

Section: Grid and Time Step Sensitivity Study And Numerical Methods V...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Numerical Study on an Oscillating Water Column Wave Energy Converter with Hyper-Elastic Material

Xiao

2022

Energies

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“…The side effect is that, as shown by the pioneering works of Budal and Falnes [5,6], the hydrodynamic interactions caused by diffracted and radiated waves between WECs can be constructive or destructive to the power output depending on the array's layout and sea state conditions, such as the wave height, wave period, wave encounter direction and water depth. In addition to the hydrodynamic interactions, there are also mechanical interactions caused by shared moorings, floaters and mechanically connected WEC components, which also influence the overall power performance of WECs in a wave park [7,8]. Moreover, the influence of the interaction effects goes far beyond changes in the power output.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic Interactions and Enhanced Energy Harnessing amongst Many WEC Units in Large-Size Wave Parks

Shao,

Ringsberg,

Yao

et al. 2024

JMSE

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Interactions between wave energy converters (WECs) can significantly affect the overall energy-harnessing performance of a wave park. Although large-size wave parks with many WEC units are commonly considered in practical applications, it is challenging to simulate such parks due to huge computational costs. This paper presents a numerical model that uses the boundary element method (BEM) to simulate wave parks. Each wave energy converter (WEC) was modelled as a comprehensive system, including WEC buoys, power take-off, and mooring systems, with hydrodynamic interactions included. Two classical layouts for arranging 16 units were simulated using this numerical model. The energy-harnessing performance of these array layouts was analyzed for both regular waves and a selection of irregular sea state conditions with different wave directions, wave heights, wave periods and water depths. For each layout, three WEC separation distances were studied. An increase of up to 16% in the power performance of the WEC under regular waves was observed, which highlights the importance of interaction effects.

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“…Sun et al [19] conducted hydrodynamic tests on a floating PA-WEC and found that intense buoy interaction can significantly decrease the optimal wave period for the wave-energy converter. According to Li et al's [20] framework, which combines CFD with a multibody dynamic structural solver, there is a persistent transient disruption in the natural frequency of the floater's pitch due to complex interactions. The intensive wave-structure interaction and wave-wave nonlinear evolution have proven to be significant sources of harmonic excitations that affect the performance of PA-WECs.…”

Section: Introductionmentioning

confidence: 99%

Experimental and CFD Assessment of Harmonic Characteristics of Point-Absorber Wave-Energy Converters with Nonlinear Power Take-Off System

Yi,

Sun,

Liu

et al. 2023

JMSE

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The wave-energy excitation of point absorbers is highly associated with their resonant movement, and harmonic characteristics are of increasing concern in affecting resonance. However, the commonly used linearized power take-off (PTO) systems underestimate the impact of harmonics. The purpose of this study is to address the knowledge gap in assessing the contribution of hydraulic PTO systems to higher harmonic wave loads and velocities. In the present work, higher harmonics in point-absorber wave-energy converters (PA-WECs) with hydraulic power take-off (PTO) systems are investigated through both experimental and computational fluid dynamics (CFD) methods. The fast Fourier transform is used to decompose the high-order harmonics. To account for the influence of nonlinear wave–wave interaction on harmonics, the isolated PA-WEC is used as a basis for comparison with the paired PA-WECs. The influence of wave steepness is also estimated at two resonance periods. Results indicate that the additional resonance of the paired PA-WECs may be attributed to the harmonic wave loads at longer wave periods. Harmonic wave loads of paired PA-WECs typically have a more substantial impact and increase more rapidly with increasing wave steepness compared to isolated PA-WECs. Furthermore, as the wave steepness increases, there are significant enhancements in both the harmonic wave loads and heaving velocity, which strongly correlate with the instantaneous maximum hydraulic power. Consequently, our study will contribute to enhancing the maximum power output in the design of future point absorber arrays.

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Coupled CFD-MBD numerical modeling of a mechanically coupled WEC array

Cited by 20 publications

References 26 publications

A Numerical Study on an Oscillating Water Column Wave Energy Converter with Hyper-Elastic Material

A Numerical Study on an Oscillating Water Column Wave Energy Converter with Hyper-Elastic Material

Hydrodynamic Interactions and Enhanced Energy Harnessing amongst Many WEC Units in Large-Size Wave Parks

Experimental and CFD Assessment of Harmonic Characteristics of Point-Absorber Wave-Energy Converters with Nonlinear Power Take-Off System

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