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1.
In this article, we investigate the energy absorption performance of a fixed-bottom pressure-differential wave energy converter. Two versions of the technology are considered: one has the moving surfaces on the bottom of the air chambers whereas the other has the moving surfaces on the top. We developed numerical models in the frequency domain, thereby enabling the power absorption of the two versions of the device to be assessed. It is observed that the moving surfaces on the top allow for easier tuning of the natural period of the system. Taking into account stroke limitations, the design is optimized. Results indicate that the pressure-differential wave energy converter is a highly efficient technology both with respect to energy absorption and selected economic performance indicators. 相似文献
2.
A. N. Fakhrutdinova V. V. Gur’yanov A. Yu. El’kin 《Izvestiya Atmospheric and Oceanic Physics》2006,42(1):60-67
The distributions of kinetic energy (KE) and available potential energy (APE) in the lower and middle atmosphere of the Northern and Southern hemispheres over the period 1992–2003 are investigated. Annual mean values of the amplitude and phase of annual and semiannual oscillations in the zonal and eddy forms of KE and APE are calculated in the height range 0–55 km (1000–0.316 hPa) for the 21st layer. A clearly pronounced annual cycle of the zonal and eddy components of KE and APE with maxima in the winter season are observed in the troposphere of both hemispheres. In the lower stratosphere, the annual-cycle maximum is shifted toward the summer season because of the meridional gradient of the zonal mean temperature. In the stratosphere of both hemispheres, along with annual oscillations, semiannual oscillations are present in all forms of energy. The intensity of these oscillations for the zonal KE and APE at the upper-stratosphere heights is comparable to the intensity of annual oscillations. A local structure of the energy regime of the upper mesosphere-lower thermosphere is investigated against the background of the global energy regime from the data of meteor sounding in Kazan. It is shown that, for both the global and regional regimes, specific features of the phase profiles of energy characteristics can be explained by the presence of barriers during the propagation of wave disturbances along the vertical. 相似文献
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Renewable energy from the ocean 总被引：3，自引：0，他引：3
Growing concern over the threat of global climate change has led to an increased interest in research and development of renewable energy technologies. The ocean provides a vast source of potential energy resources, and as renewable energy technology develops, investment in ocean energy is likely to grow. Research in ocean thermal energy conversion, wave energy, tidal energy, and offshore wind energy has led to promising technologies and in some cases, commercial deployment. These sources have the potential to help alleviate the global climate change threat, but the ocean environment should be protected while these technologies are developed. Renewable energy sources from the ocean may be exploited without harming the marine environment if projects are sited and scaled appropriately and environmental guidelines are followed. 相似文献
4.
Aurélien Babarit 《Ocean Engineering》2010,37(8-9):718-729
In this paper, wave farms composed of two either surging or heaving wave energy converters are considered. Using a numerical model which takes into account wave interactions, the impact on the absorbed wave power of the separating distance between the two systems and the wave direction is studied. In regular waves, a modified qmod factor is introduced and it is found to be more relevant than the usual q factor for identifying this impact. Then, it is shown that, asymptotically, the alteration of the energy absorption due to wave interaction effects decreases with the square root of the distance. This is a slow decay, which leads to a still significant modification of the wave energy absorption at long distance (up to 15% at a distance of 2000 m). In irregular waves, it is shown that constructive and destructive effects compensate each other, particularly when considering the mean annual power. It leads to a smaller impact of the wave interactions on the absorbed energy and shorter distances (smaller than 10% for distances greater than 400 m). Finally, conclusions on if wave interactions should be taken into account or not when designing a wave farm are drawn in function of the distance. 相似文献
5.
中国海域波浪能资源分布及波浪能发电装置适用性研究 总被引：1，自引：1，他引：0
首先全面综述了国内外波浪能资源开发利用现状,系统总结了目前国内外海洋波浪能资源发电技术中应用的主要波浪能资源开发装置及存在问题;基于ERA-Interim再分析数据,给出了中国海域的平均波浪能流密度和季节特征,从而获取高波能资源分布区域,得到了中国海域波浪能资源分布富集区域;结合不同海岸岸线及海底类型,综合给出了中国波能资源富集区域中发电装置适用建议、高峰发电季节。对提高我国波浪能资源开发利用、推动海洋可再生能源行业的发展具有重要意义,也为实用化、商业化海洋波浪能资源选址提供了科学依据。 相似文献
6.
The characteristics of ocean wind waves place certain constraints upon devices designed to convert their energy to a useful form. Here we consider the nature of these constraints and the theoretical analysis of a wave power generator that conforms to the design criteria. We also present the results of field tests with several models of the wave power generator. The experimental results support the theory and indicate that such a wave pump is suitable for power generation in a variety of circumstances. 相似文献
7.
考虑发电机尾流作用的潮流能理论可开发量的评估 总被引：1，自引：1，他引：0
In this study, we construct one 2–dimensional tidal simulation, using an unstructured Finite Volume Coastal Ocean Model(FVCOM). In the 2–D model, we simulated the tidal turbines through adding additional bottom drag in the element where the tidal turbines reside. The additional bottom drag was calculated from the relationship of the bottom friction dissipation and the rated rotor efficiency of the tidal energy turbine. This study analyzed the effect of the tidal energy turbine to the hydrodynamic environment, and calculated the amount of the extractable tidal energy resource at the Guishan Hangmen Channel, considering the rotor wake effect. 相似文献
8.
A wave power device includes an energy harvesting system and a power take-off system. The power take-off system of a floating wave energy device is the key that converts wave energy into other forms. A set of hydraulic power take-off system, which suits for the floating wave energy devices, includes hydraulic system and power generation system. The hydraulic control system uses a special“self-hydraulic control system”to control hydraulic system to release or save energy under the maximum and the minimum pressures. The maximum pressure is enhanced to 23 MPa, the minimum to 9 MPa. Quite a few experiments show that the recent hydraulic system is evidently improved in efficiency and reliability than our previous one, that is expected to be great significant in the research and development of our prototype about wave energy conversion. 相似文献
9.
In this study we investigate how the wave energy deficit in the lee of an array of overtopping type wave energy converting devices (WECs), redistributes with distance from the array due to the natural variability of the wave climate and wave structure interactions. Wave directional spreading has previously been identified as the dominant mechanism that disperses the wave energy deficit, reducing the maximum wave height reduction with increasing distance from the array. In addition to this when waves pass by objects such as an overtopping type WEC device, diffracted waves re-distribute the incident wave energy and create a complex interference pattern. The effect of wave energy redistribution from diffraction on the wave energy shadow in the near and far field is less obvious. In this study, we present an approximate analytical solution that describes the diffracted and transmitted wave field about a single row array of overtopping type WECs, under random wave conditions. This is achieved with multiple superpositions of the analytical solutions for monochromatic unidirectional waves about a semi-infinite breakwater, extended to account for partial reflection and transmission. The solution is used to investigate the sensitivity of the far field wave energy shadow to the array configuration, level of energy extraction, incident wave climate, and diffraction. Our results suggest that diffraction spreads part of the wave energy passing through the array, away from the direct shadow region of the array. This, in part, counteracts the dispersion of the wave energy deficit from directional spreading. 相似文献
10.
This paper extends the theory on capture width, a commonly used performance indicator for a wave energy converter (WEC). The capture width of a linear WEC is shown to depend on two properties: the spectral power fraction (a property introduced in this paper), which depends entirely on the sea state, and the monochromatic capture width, which is determined by the geometry of the WEC and the chosen power take off (PTO) coefficients. Each of these properties is examined in detail. Capture width is shown to be a measure of how well these two properties coincide. A study of the effects of PTO control on the capture width suggests that geometry control, a form of control that has not been the focus of much academic research, despite its use in the wave energy industry, deserves more attention. The distinction between geometry control and PTO control is outlined. While capture width is a valuable design tool, its limitations must be recognised. The assumptions made in the formulation of capture width are listed, and its limitations as a tool for estimating annual power capture of a WEC are discussed. 相似文献
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利用ECOM模式模拟南海正压M2、S2、K1、O1分潮, 对南海潮能通量及潮能耗散进行研究.结果显示, M2、S2、K1和O1分潮分别有38.93、5.77、29.73和28.97GW的能通量经吕宋海峡传入南海, 并有2.42、0.36、8.67和7.86GW的能通量由南海经卡里马塔海峡传入爪哇海.由东海及吕宋海峡西北部传入台湾海峡的M2分潮能通量为25.28GW.半日潮进入北部湾和泰国湾的能通量较少(6.52GW), 全日潮则较大(24.74GW).通过民都洛和巴拉巴克海峡断面, 全日潮由南海向苏禄海共输送12.28GW的能通量, 而半日潮则由苏禄海向南海输送1.92GW的能通量.由模式输出结果估计得到的南海各局部海域的底摩擦耗散与净潮能通量存在差异, 为使二者平衡, 可对南海不同海域的底摩擦系数进行调整.依净潮能通量与底摩擦耗散平衡关系计算得到台湾海峡、北部湾、泰国湾及南海深水海域的底摩擦系数分别为0.0023、0.0024、0.0023和0.0021. 相似文献
13.
Hiroshi Ichikawa 《Journal of Oceanography》1978,34(4):129-139
The spectral energy balance in the wind-wave spectrum is studied with taking into account the energy input from turbulent wind to waves, the energy rearrangement due to conservative nonlinear wave-wave interaction and the energy dissipation due to water turbulence. Using the Ichikawa's (1978) model on the turbulent wind field over wind-waves and assuming that the energy dissipation is times greater than that due to molecular viscosity of water, the energy input and dissipation are determined so as to satisfy the condition that the nonlinear-transfers of momentum and energy conserve the total momentum and energy of waves. The nonlinear energy-transfer is estimated from the energy balance at each frequency. It is found that the energy input and dissipation satisfying the condition on the conservative nonlinear-transfer are determined by the characteristic height of wind-wave field and the friction velocity of air, and that the spectral distribution of the nonlinear energy-transfer estimated in this paper is qualitatively similar to that estimated by the non-linear wave-wave interaction theory ofHasselmann (1962). 相似文献
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Tosio Nan-niti 《Journal of Oceanography》1984,40(6):405-409
To refine the previous hypothesis of turbulent energy spectrum (Nan-niti, 1970), further theoretical consideration and a simple
experiment using electric fans was carried out. From the hypothesis ofq=δε/δk andεq=const., the following relations are derived for the spectrumF, and the autocorrelation functionR:F(k)∼k
−(5−2α)/3 andR(t)∼1−(t/τ)2(1−α)/3, whereq is the local energy supply,ε the energy dissipation rate, andk the wavenumber,t the time,τ the lifetime of the largest eddy. The following further relations are also obtained:ε∼l
−α,v∼l
β,v∼τ
γ andγ=(1−α)/(2+α)=β/(1−β), wherel is the length scale of the phenomenon,v turbulent velocity,α=1/2,β=1/6, andγ=1/5. The experimental results support these relations. 相似文献
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This paper provides a linear solution for the Wave Rotor, a wave energy device that comprises two parallel counter rotating cylinders in orbital motion. Theoretical results are obtained for the radiated waves generated by the device, and for its efficiency. Comparisons with earlier measurements of radiated waves show very promising agreement. 相似文献
19.
The tidal volume transport in the Seto Inland Sea is calculated. The cross-section where the volume transport of the M2 tide is zero, is located around the western part of Bisan Strait. The tidal energy dissipation of the M2 tide by friction is 6.30×1016 ergs s–1 in the Seto Inland Sea. The quality factorQ for the M2 tide is 20.2. The total energy dissipation of the M2, S2, K1 and O1 tides is 7.99×1016 ergs s–1. 相似文献
20.
This paper addresses the Archimedes Wave Swing (an offshore wave energy converter, which produces electricity from sea waves). It compares the performances of latching control (a discrete, highly non-linear, intrinsically sub-optimum control strategy), of reactive control, of phase and amplitude control (two optimum control strategies that involve non-causal transfer functions, which have to be implemented with approximations, thus rending the control sub-optimum), and of feedback linearisation control (a non-linear control strategy). From extensive simulations it is concluded that the latter performs clearly better irrespective of the sea state, and leads to a significant increase of absorbed wave power. 相似文献