特定波形玫瑰图条件下底铰式襟翼波能转换装置的优化（英文）

In this paper, we conducted a numerical analysis on the bottom-hinged flap-type Wave Energy Convertor(WEC). The basic model, implemented through the study using ANSYS-AQWA, has been validated by a three-dimensional physical model of a pitching vertical cylinder. Then, a systematic parametric assessment has been performed on stiffness, damping, and WEC direction against an incoming wave rose, resulting in an optimized flap-type WEC for a specific spot in the Persian Gulf. Here, stiffness is tuned to have a near-resonance condition considering the wave rose, while damping is modified to capture the highest energy for each device direction. Moreover, such sets of specifications have been checked at different directions to present the best combination of stiffness, damping, and device heading. It has been shown that for a real condition, including different wave heights, periods, and directions, it is very important to implement the methodology introduced here to guarantee device performance.     

基于Star-CCM+的摆式波浪能装置水动力性能研究（英文）

A two-dimensional numerical Computational Fluid Dynamics(CFD) model is established on the basis of viscous CFD theory to investigate the motion response and power absorption performance of a bottom-hinged flap-type wave energy converter(WEC)under regular wave conditions. The convergence study of mesh size and time step is performed to ensure that wave height and motion response are sufficiently accurate. Wave height results reveal that the attenuation of wave height along the wave tank is less than 5% only if the suitable mesh size and time step are selected. The model proposed in this work is verified against published experimental and numerical models. The effects of mechanical damping, wave height, wave frequency, and water depth on the motion response, power generation, and energy conversion efficiency of the flap-type WEC are investigated. The selection of the appropriate mechanical damping of the WEC is crucial for the optimal extraction of wave power. The optimal mechanical damping can be readily predicted by using potential flow theory. It can then be verified by applying CFD numerical results. In addition, the motion response and the energy conversion efficiency of the WEC decrease as the incident wave height increases because the strengthened nonlinear effect of waves intensifies energy loss. Moreover, the energy conversion efficiency of the WEC decreases with increasing water depth and remains constant as the water depth reaches a critical value. Therefore, the selection of the optimal parameters during the design process is necessary to ensure that the WEC exhibits the maximum energy conversion efficiency.     

双浮体波浪能装置的振荡和能量转换特性研究（英文）

In this study, we investigated the hydrodynamic and energy conversion performance of a double-float wave energy converter(WEC) based on the linear theory of water waves. The generator power take-off(PTO) system is modeled as a combination of a linear viscous damping and a linear spring. Using the frequency domain method, the optimal damping coefficient of the generator PTO system is derived to achieve the optimal conversion efficiency(capture width ratio).Based on the potential flow theory and the higher-order boundary element method(HOBEM), we constructed a threedimensional model of double-float WEC to study its hydrodynamic performance and response in the time domain. Only the heave motion of the two-body system is considered and a virtual function is introduced to decouple the motions of the floats. The energy conversion character of the double-float WEC is also evaluated. The investigation is carried out over a wide range of incident wave frequency. By analyzing the effects of the incident wave frequency, we derive the PTO's damping coefficient for the double-float WEC's capture width ratio and the relationships between the capture width ratio and the natural frequencies of the lower and upper floats. In addition, it is capable to modify the natural frequencies of the two floats by changing the stiffness coefficients of the PTO and mooring systems. We found that the natural frequencies of the device can directly influence the peak frequency of the capture width, which may provide an important reference for the design of WECs.     

波浪能供电航标转换效率的实验研究

采用可再生能源中的波浪能为航标供电,是解决航标供能的有效方式。本文以为航标供电的振荡水柱式波浪能发电装置为研究对象,开展不同工况及负载对振荡水柱式波浪能发电装置转换效率影响的研究,确定最高效率下波浪能装置的各类参数值。通过物理模型试验结果表明,获得的最佳效率点在T=2.5s时,H=104mm,转换效率最大为35%。振荡水柱式波浪能发电装置的能量转换效率受负载影响较小,受波浪要素中波高和周期的影响较大,特别是受波高周期比影响较大。本试验结果对优化振荡水柱式波浪能发电装置的方向提供指导意义,有助于进一步研究。     

双重卡口机构对波浪能转换器性能的影响评估（英文）

Lower efficiencies induce higher energy costs and pose a barrier to wave energy devices' commercial applications.Therefore,the efficiency enhancement of wave energy converters has received much attention in recent decades.The reported research presents the double snap-through mechanism applied to a hemispheric point absorber type wave energy converter(WEC) to improve the energy absorption perfomance.The double snap-through mechanism comprises four oblique springs mounted in an X-configuration.This provides the WEC with different dynamic stability behaviors depending on the particular geometric and physical parameters employed.The efficiency of these different WEC behaviors(linear,bistable,and tristable) was initially evaluated under the action of regular waves.The results for bistable or tristable responses indicated significant improvements in the WEC' s energy capture efficiency.Furthermore,the WEC frequency bandwidth was shown to be significantly enlarged when the tristable mode was in operation.However,the corresponding tristable trajectory showed intra-well behavior in the middle potential well,which induced a more severe low-energy absorption when a small wave amplitude acted on the WEC compared to when the bistable WEC was employed.Nevertheless,positive effects were observed when appropriate initial conditions were imposed.The results also showed that for bistable or tristable responses,a suitable spring stiffness may cause the buoy to oscillate in high energy modes.     

系泊系统对波能发电装置动力响应的影响

[目的]为了设计造价合理、性能高效的系泊系统,研究不同系泊系统对波能发电装置(WEC)的能量摄取(PTO)能力和定位性能的影响.[方法]选择一典型的两刚体点吸式WEC装置为研究对象,采用WEC-Sim和MoorDyn开源代码设计两类系泊系统,一类采用锚链,另一类采用锚链和聚酯缆绳所组成的混合缆.通过对这两类系泊系统进行...     

Parametric study of two-body floating-point wave absorber

In this paper, we present a comprehensive numerical simulation of a point wave absorber in deep water. Analyses are performed in both the frequency and time domains. The converter is a two-body floating-point absorber (FPA) with one degree of freedom in the heave direction. Its two parts are connected by a linear mass-spring-damper system. The commercial ANSYS-AQWA software used in this study performs well in considering validations. The velocity potential is obtained by assuming incompressible and irrotational flow. As such, we investigated the effects of wave characteristics on energy conversion and device efficiency, including wave height and wave period, as well as the device diameter, draft, geometry, and damping coefficient. To validate the model, we compared our numerical results with those from similar experiments. Our study results can clearly help to maximize the converter’s efficiency when considering specific conditions.     

时段选取对波浪玫瑰图绘制的影响

利用Matlab数据库工具箱实现了对水文观测数据库数据的调用。基于日照海洋观测站10年实测资料,编程绘制了不同时段的波浪玫瑰图,比较分析了时段的长短对波浪玫瑰图绘制的影响。结果表明,日照港宜采用不少于5年的实测资料,由此绘制的波浪玫瑰图才能反映不同波级在各个方向上的长期变化趋势。     

Estimation of the wave direction of ship waves generated by a small vessel using the multiple signal classification method

It is very important to estimate the waves generated by a small vessel so as to investigate their effects on floating bodies within the scope of fisheries and ocean engineering. Simplified methods for estimating the wave heights and periods of ship waves have been presented in previous studies. However, estimating the direction of ship waves is not easy. The focus of the present study is to develop an analytical technique to determine the direction of ship waves based on the measurements in field experiments. The multiple signal classification (MUSIC) method is newly proposed for determining the direction of ship waves. For high ship speeds, the directional spectrum of ship waves estimated by MUSIC resulted in a sharp monotone peak, and the estimated directions of ship waves were very similar to the results of field experiments using an actual small vessel. The proposed MUSIC method has thus been confirmed to be effective in estimating ship wave directions with high resolution.     

粘性流体数值波浪水池研究

数值波浪水池是近年来船舶流体力学方向的前沿课题,本文采用Fluent软件,利用VOF模型捕捉自由液面,结合RNGk?ε湍流模型,求解N-S方程,对目前数值造波较为典型的仿物理造波法和直接造波法在二维模式下进行分析,并对三维模式的数值造波作了初步分析.在仿物理造波法中模拟真实水池中推板式造波机,利用动网格和阻尼消波技术,生成规则波的情况.在直接造波法中,利用给定入口边界速度或压力并结合阻尼消波技术,在数值水池模拟规则波,得到直接造波法的数值波形与理论波形的吻合度要优于仿物理造波法的结果.为在数值波浪水池中对船舶水动力性能预报奠定基础.     

波浪入射角度对立柱周围波面扰动特性的影响研究

基于N-S方程和连续性方程建立了三维数值波浪水池,并在该水池内对固定直立柱在不同浪向下的波浪爬升和绕射问题进行了数值模拟。为了验证数值计算的准确性,对立柱近壁面处的波浪爬升效应展开了模型试验研究,计算值与试验值吻合较好,证明了该方法的可行性。研究了入射角度的变化对立柱周围波浪爬升幅度和非线性特征的影响,同时从垂直浪向的投影面积和相对浪向的投影面形状这两个因素出发,探讨了不同浪向角下立柱周围的波浪叠加、波面放大率以及二次波峰效应,并对自由面漩涡生成特性进行了较为深入的机理性研究,可为今后进一步研究不同的入射角度下,复杂的海洋结构物周围的波浪非线性效应提供有价值的参考。     

An appropriate unidirectional wave spectrum model for the Strait of Hormuz

The objective of this paper is to introduce an appropriate unidirectional wave spectrum model for the Strait of Hormuz. The research is focused on assessing performance of standard wave spectrum models in the region. By evaluating such models based on valuable measurement data recently published, the calibration procedure has been conducted on such standard models to reach a better concordance between a modified standard spectral model and observed field spectra. The calibration is performed initially with respect to four distinct directions related to four available measurement stations. So, it results in four sets of coefficients for a nominated model. Next, it is continued to reach just one model insensitive to directions. Results clearly showed that the International Towing Tank Conference (ITTC) model is more appropriate than Joint North Sea Wave Project (JONSWAP) and Pierson and Moskowitz (PM) models in this area, even without any calibration. However, modifications have been successful on improving the conformity of the model.     

大连海域波浪特征研究

根据大连及其附近海域11个站的波浪实测资料,研究分析了大连海域不同岸线段的波浪基本特征,包括常浪向、强浪向及其频率等,绘制了波浪玫瑰图;根据有关文献,对大连海域不同岸线外海深水波浪要素特征进行了分析研究,给出了50a一遇强浪向的波高和周期.结果表明:大连海域在渤海侧强浪向主要为偏北向,黄海侧海域的强浪向主要是偏南向.     

规则波作用下斜坡堤越浪量的数值模拟

台风过境产生极端波浪造成斜坡式海堤越浪,现有计算越浪量的经验公式都存在适用性的问题.为探求台风天气下舟山区域斜坡堤越浪量计算公式,基于VOF方法,对Navier-Stokes方程和k-ε方程进行求解,建立速度边界造波和阻尼消波的数值波浪水槽.在水槽中建立斜坡堤模型,通过改变影响越浪量的相关因素,模拟台风浪条件下规则波作...     

斜向波浪对斜坡堤胸墙作用力的试验研究

斜坡堤胸墙的稳定性主要受到波浪作用的影响,而且实际工程中斜坡堤多受斜向波浪作用。通过斜向与正向不规则波对斜坡堤胸墙作用的物理模型试验研究,分析斜坡堤单个胸墙所受的斜向波浪总力的折减系数随水位和波浪入射角度的变化规律,并与斜向波浪对单元直立堤的作用情况进行对比。结果表明:斜坡堤单个胸墙所受的斜向波浪总力的折减系数总体上随着水位的降低而变小,随着波浪入射角度的减小而变小;斜向波浪总浮托力的折减系数一般小于总水平力的折减系数;在不同水位和波浪入射角下,斜坡堤单个胸墙所受的斜向波浪总力的折减系数与单元直立堤有一定差别。     

Equivalent linear pseudostatic and dynamic modelling of vertically vibrating monopile

To optimize offshore wind turbine (OWT) design, an engineering tool has been developed allowing for a detailed investigation of the effects of nonlinear soil stiffness and damping on foundation dynamics. We have studied the response of a vertically oscillating offshore wind monopile foundation in a realistic soil profile subjected to loads between 1 and 200 MN in the frequency range 0–10 Hz with pseudo-static and equivalent linear dynamic model. The non-linear soil behaviour is modelled with an equivalent linear method with shear modulus reduction and damping curves as input. The tool is verified and validated by comparison with elasto-dynamic model and experiments. With increasing load amplitudes foundation stiffness increases and damping decreases. For large load amplitudes the lower part of the pile foundation contributes more to foundation damping. The results indicate the nonlinear foundation stiffness and damping can be modelled rationally by combining stiffness and hysteretic damping from nonlinear static tools with apparent mass and radiation damping from elasto-dynamic analysis. The tool can be used to compute soil springs and dampers based on laboratory-based soil stiffness and damping.     

鹰式装置“万山号”总体设计概述

100kW鹰式波浪能发电装置工程样机“万山号”为一基多体式设计,四个鹰式吸波浮体共享水下附体、能量转换系统及锚泊系统。通过一系列模型试验,获得最优负载。根据模型试验结果,确定了实海况装置的出力参数。为稳定地获得标准电力与试验数据,设计了涵盖蓄能、发电、变电模块、电气监控模块、电源模块、浮态监控模块和岸基模块等多个模块的电气系统。通过锚泊系统计算与分析,确定了锚泊系统的选型参数。     

栾家口和蓬莱东港区波浪特性与掩护水域波况研究

根据龙口、蓬莱海洋站实测波浪资料,分析烟台港栾家口港区和蓬莱东港区的波浪特性,结果显示该海区属于以风浪为主、涌浪为辅的混合浪。利用TK-2D的PEM波浪数学模型模拟工程前波浪,得到工程区设计波要素,栾家口港区的强浪向是偏WNW向,蓬莱东港区的强浪向是偏NE向。利用MIKE21的BW方程波浪数学模型对平面布置方案下港内的波况进行模拟。在掩护水域由于采用直立式码头,波浪发生多次反射,码头前波高较大,为减小港内波高,对方案进行优化,采用高桩等反射率小的码头结构型式,可以消散港内波能,有效减小码头前波高。     

基于CFD粒子法的波能转换装置水动力模拟（英文）

Wave energy from the ocean is currently a very popular renewable energy, and its development has primarily focused on the shape of the wave energy converter(WEC) used to efficiently convert wave energy into electrical energy. However, the free surface ocean wave problem is very complex and the parameters affecting WEC behavior are difficult to understand. In this paper, based on the Lattice-Boltzmann method, we present particle-based CFD simulation results for the pivoted-type WEC that exhibits both vertical and horizontal motions. In this method, the computation domain need not be a mesh and complex geometry is not a limiting factor. Using a free-surface turbulence model, we simulated the fluid-structure interaction. We detail our simulation results, which show good agreement with those in the literature.     

鹰式波浪能发电装置水动力学性能分析及优化

根据牛顿第二定律,对鹰式波浪能装置多个浮体进行了力学分析,基于微波理论,通过每个浮体之间三种模态的运动耦合,建立了流体力、阻尼力、铰接力、静水回复力等内外力之间的力学方程组。通过以运动浮体为边界条件求解多个浮体的水动力学参数,代入方程组中计算求得最优外加阻尼和最优俘获宽度比,从而优化设计方案,得到此时各浮体在纵荡、垂荡和纵摇三种运动模态下的位移幅值,以及阻尼力、铰接力、液压缸运动速度等相关参数。研究成果为鹰式波浪能装置的设计及制造提供了理论参考和依据。