共查询到20条相似文献，搜索用时 31 毫秒
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为研究浮冰在波浪下的运动特性,以单个聚氯乙烯（PVC）塑料圆板模拟浮冰,进行了一系列波浪试验研究。在规则波试验基础上,同时研究了双色波条件下的浮冰运动特性。结果显示：规则波条件下浮冰运动幅频响应算子首先随无量纲波长的增大而增大,当无量纲波长大于4.0后,运动幅频响应算子随无量纲波长的变化不明显,且趋于一定值;在双色波条件下,对应频率组成成分的浮冰运动幅频响应算子与规则波条件下随波长的变化规律一致。根据部分规则波试验结果提出预测浮冰慢漂速度的经验公式,并用已有的试验和余下的规则波与双色波试验结果进行验证。结果表明,经验公式对规则波和双色波条件下的浮冰慢漂速度的误差在20%以内,预测结果吻合较好。 相似文献
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A towing experiment was conducted using a modulated wave train to investigate the vertical bending responses of a hydro-structural container ship model. In the experiment, a spatially periodic modulated wave train, as a model of a freak wave in successive high waves mimicking the so-called three sisters, was generated by the recently established higher-order spectral method wave generation (HOSM-WG) method. HOSM-WG enables us to control the location and timing of the maximum crest height in a wave tank. With precise control of the towing carriage, an experiment was conducted in which the timing of the encounters between the ship model and the modulated wave train was accurately determined. The maximum sagging moment (SM) was found to increase in proportion with the encounter wave height. However, because of differences in the relative depth of the fore and aft troughs, the maximum SM is highly variable for a given wave height. The temporal wave-geometry evolution caused the relative trough-depth to vary significantly within a wave period in the vicinity of the maximum crest height. As a result, depending on the encounter timing, the SM varied considerably for a given wave height. The temporal variation of the wave geometry is a robust feature of a modulated wave train and is common between the spatially periodic and temporally periodic modulated wave trains. 相似文献
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A direct-drive wave energy conversion system based on a three-phase permanent magnet tubular linear generator （PMTLG） and a heaving buoy is proposed to convert wave energy into electrical energy. Sufficient experimental methods are adopted to compare the computer simulations, the validity of which is verified by the experiment results from a wave tank laboratory. In the experiment, the motion curves of heaving buoy are with small fluctuations, mainly caused by the PMTLG＇s detent force. For the reduction of these small fluctuations and a maximum operational efficiency of the direct-drive wave energy conversion system, the PMTLG＇s detent force minimization technique and the heaving buoy optimization will be discussed. It is discovered that the operational efficiency of the direct-drive wave energy conversion system increases dramatically after optimization. The experiment and optimization results will provide useful reference for the future research on ocean wave energy conversion system. 相似文献
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波浪的方向分布对波浪的传播及其与工程结构物的作用都具有明显影响,目前现有的研究大多是基于单向波浪进行的。为了研究方向分布对群墩结构上的爬高影响,基于规则波浪与群墩作用的理论解,结合多向不规则波浪的造波方法,建立了多向不规则波浪与群墩作用的计算模型,同时进行了物理模型试验对模型的有效性进行了验证。系统地对群墩周围及表面上的波浪爬高进行了计算分析,结果表明,方向分布对波浪爬高具有较大的影响,且不同位置处的影响并不相同,在实际的工程设计中如果按照单向波浪计算,可能低估或者高估群墩周围的爬高。 相似文献
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不同掩护程度弧形胸墙波压力及越浪量试验研究 总被引：1，自引：0，他引：1
为了明确斜坡堤弧形胸墙越浪量及波压力的变化规律,采用波浪水槽试验测量了弧形胸墙的越浪量和波压力。试验从斜坡堤弧形胸墙前的掩护程度等因素入手对弧形胸墙的返浪效果及波压力进行初步研究,得出不同掩护程度弧形胸墙的越浪量及波压力,发现掩护程度越好,弧形胸墙所受波压力越小;半掩护情况下越浪量最小,为实际工程设计提供了依据。 相似文献
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通过物理模型实验,对沙质海床上沉入式大直径圆筒结构对波浪的动态响应进行了较系统的实验研究。实验中考虑了大直径圆筒、波浪和海床三者之间的耦合作用,并实时记录了大直径圆筒结构的动态响应。实验数据分析表明,大直径圆筒在波浪作用下的动态响应以大圆筒随波浪的前后摆动为主,其摆动轴心并不是固定不变的。最后通过回归分析给出了估算大直径圆筒摆动转角幅值的经验公式。 相似文献
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This paper is focussed on the derivation of a set of general scaling laws valid for both beach and dune erosion volumes based on scaling law analysis, existing and new experimental results. This latter experiments concern beach profile changes in three different laboratory flumes using identical wave conditions based on Froude scaling. The experiments with planar sloping beaches have been done at three scales: large-scale Hannover wave flume experiment (beach slope of 1 to 15), medium scale Barcelona wave flume experiment (beach slope of 1 to 15) and small-scale Delft wave flume experiments (beach slopes of 1 to 10, 15 and 20) using an identical wave train of irregular waves (single topped spectrum). 相似文献
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海岸沙坝近底悬移质通量实验研究 总被引：1，自引：0，他引：1
为了研究海岸沙坝的产生和演化机理,对不规则波和波群作用下沙坝上方的近底悬移质通量进行了实验研究。分析了短波、长波和平均水流对悬移质通量的影响。结果表明:各种波况下平均水流和长波的作用始终使泥沙向离岸方向输移,而短波的作用使泥沙向岸方向运动;平均水流引起的泥沙输移始终占主要成分,长波的次之。不规则波情况下平均水流的影响较规则波的情况相对较弱,三种成分对泥沙输运的贡献属于同一量级。波群情况下长波的影响随着波浪群性的增强而加大,短波的不明显,而平均水流的影响则随着波浪群性的增强而减弱。 相似文献
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Before a reflecting wall, the wind waves strongly differ from the periodic waves. The nodes and the antinodes tend to disappear starting one wave length from the wall. The wave period, as a function of the distance from the wall, exhibits some negative discontinuities at the nodes. Those properties were predicted from an analysis of theoretical spectra and were confirmed by an experiment which employed 30 wave gauges at sea. The experiment revealed also a characteristic pressure-fall under the crests of the highest waves at the wall. The phenomenon was related to high water jets detected at the centers of the wave fronts. 相似文献
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The SWAN model used to study wave evolution in a flume 总被引：1，自引：0，他引：1
Deborah J. Wood Research Assistant Markus Muttray Research Engineer Professor Hocine Oumeraci 《Ocean Engineering》2001,28(7)
The SWAN numerical model is used to model the evolution of JONSWAP wave spectra and hence the significant wave height of waves in a tank. Comparison with experiment has shown that modelling triad interactions in the numerical model leads to too low predictions of spectra and significant wave height and should therefore be excluded. The modelling of the breaking constant was also investigated, by looking at the use of a constant breaking constant, Nelson formula, and Goda formula (added into SWAN for this study). Using a constant value of 0.78 within SWAN gave the best comparison between theory and experiment. 相似文献
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The form of Boussinesq equation derived by Nwogu （1993） using velocity at an arbitrary distance and surface elevation as variables is used to simulate wave surface elevation changes. In the numerical experiment, water depth was divided into five layers with six layer interfaces to simulate velocity at each layer interface. Besides, a physical experiment was carried out to validate numerical model and study solitary wave propagation.“Water column collapsing”method （WCCM） was used to generate solitary wave. A series of wave gauges around an impervious breakwater were set-up in the flume to measure the solitary wave shoaling, run-up, and breaking processes. The results show that the measured data and simulated data are in good agreement. Moreover, simulated and measured surface elevations were analyzed by the wavelet transform method. It shows that different wave frequencies stratified in the wavelet amplitude spectrum. Finally, horizontal and vertical velocities of each layer interface were analyzed in the process of solitary wave propagation through submerged breakwater. 相似文献
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1.Introduction Owingtoitssignificanteffectofreductionofwaveloadsandwaverun up,theperforatedwallon anarrayofcylindricalstructureshasreceivedconsiderableattentioninrecentyears.Manyresearches havebeencarriedoutinthisfield.Anexactsolutionforthediffractionoflinearwaterwaveswithan arrayofimpermeablecylinderswasfirstgivenbySpringandMonkmeyer(1974)usinganeigenfunction expansionapproach.Subsequently,LintonandEvans(1990)madeamajorsimplificationtothetheo ry,whichallowedthenear fieldquantitiessuchasload… 相似文献
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珊瑚岛礁海岸波流动力复杂、地貌形态特殊、工程响应未知, 波浪传播变形和波生环流对建筑物安全、地形地貌演变、防灾减灾和生态环境保护都有重要影响。本文从大范围大洋海脊导波与岛礁波浪俘获、中等尺度的礁坪-潟湖-裂口系统波流特性、建筑物前沿的局部波流特性及工程响应等三种不同空间尺度上综述了波流运动特性研究的新进展, 主要包括深水大范围的海脊波浪引导与岛礁波浪俘获的理论解析、礁坪-潟湖-裂口系统整体物理模型实验、基于大水槽实验的建筑物影响下波流演化过程及越浪量和波浪力计算方法, 并提出亟需深入研究的重点内容。 相似文献
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The double-body heave wave energy converter(WEC) is one of the most conducive devices to absorb the wave energy from relative motion while the law of which is not well understood. This paper makes an in-depth study on this wave energy converter, by means of the combination of theoretical analysis and physical model experiment. The hydrodynamic characteristics and energy capture of the double-buoy under constant and linear Power Take-Off(PTO) damping are investigated. Influences of absolute mass and mass ratio are discussed in the theoretical model.Relative displacement amplitude and average power output are tested in the experiment to analyze the effect of the wave period and outer buoy's mass, while the capture width ratio(CWR) is also calculated. Results show that the wave period and mass of the buoys have a significant effect on the converter. Different forms of PTO damping have no influence on the optimal wave period and mass ratio of this device. It is recommended to select the double-buoy converter with a mass ratio of 0.80 and to place it in an area with the frequent wave period close to the natural period of the outer buoy to achieve the optimal energy capture. 相似文献
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An analytical solution is proposed to predict the wave set-up over permeable reef flat based on porous flow model and momentum conservation. A laboratory experiment is carried out to verify the analytical solution. Good agreement is obtained by comparing the analytical results and the experimental data. Both the analytical results and the experimental data show the wave setup increases with the increase of the incident wave height and the decrease of the submergence water depth. The influences of the porous properties of the coral reef on wave set-up are discussed based on the analytical solution and experiment results. The wave set-up on the reef flat is found to decrease with the increasing particle size of porous media layer. The increase of the porosity and the height of porous media layer can lead to significant reduction in the wave set-up on the reef flat. 相似文献
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近岸植物带能有效削弱波浪作用,植物带消浪影响因素分析对布置护岸工程、维护岸线稳定有重要意义。在模型实验基础上,探究相对波高、模型相对宽度、模型相对高度和体积分数对透射系数的影响。设置波浪水槽试验,研究孤立波在不同水深、入射波高及植物排布方式等组合条件下对植物消浪效果的影响。采用遗传编程法得出各复杂度下的透射系数计算公式,并分析各参数在方程中的表现情况,发现遗传编程能定性给出参数的敏感度。相比于非线性回归拟合结果,遗传编程方法得到的函数关系更加精确。采用人工神经网络方法进一步分析与验证各影响因素对植物消浪效果的影响程度,结果表明人工神经网络得出的结果与遗传编程方法相近,体积分数对消浪效果起主导作用。 相似文献
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波群对垂直桩柱的作用力 总被引：1，自引：0，他引：1
在波浪槽中进行了具有不同群因子和连长的随机波群对三种直径的桩柱作用力的实验研究,指出波浪峰力的比值不随波群的连长变化,而随波群因子的增加而增大。由于桩柱是一非线性系统,作用力的群团子大于波浪的群因子,其连长小于波浪的连长。波浪峰力的比值不仅随KC数的增加而增大,还随波群因子GF的增加而增大。 相似文献