近岸海域波浪场中污染物运动的实验研究

通过实验模拟,研究了缓坡海岸带(坡度为1:100和1:40)波浪场中污染物的运动.给出了污染物在波浪破碎区和非破碎区运动范围的变化,讨论了在规则波和非规则波作用下波浪破碎区和非破碎区污染物运动的宏观变化趋势.     

沿岸流中混合系数的实验研究

进行了在规则波作用下破波带内水平混合系数测量的物理模型实验。通过在沿岸流流场中投放墨水点源和采用CCD摄像机摄像,测量了点源扩散过程。利用水深平均二维扩散方程近似解析解得到了由实验结果计算混合系数的方法。实验结果表明:扩散系数仅依赖于当地水深,与波浪参数(周期和波高)无关。沿岸流沿水深变化产生的离散作用导致顺流方向(纵向)混合系数远大于横流方向(横向)混合系数。横流方向混合系数中由波浪产生的扩散系数占总扩散系数约40%,其余为波浪破碎引起的湍流产生的扩散系数。     

波浪破碎下湍流混合的实验研究

波浪破碎过程产生的湍流动量和能量垂向输运对于加快海洋上混合层中垂向混合具有显著效果.采用二维实验室水槽中对波浪破碎过程进行模拟.对采集的波浪振幅时间序列采用希尔伯特变换定位破碎波位置,波浪的破碎率随有效波高的增加而增大,波浪谱分析得到的波浪基本周期与有效周期结果相似.实验中采用粒子图像测速技术(particle ima...     

基于水槽实验的近岸波浪破碎计算研究

将前人波浪破碎计算及判定公式进行汇总、整理并分成3类;同时,为了对选取公式进行比较,文还将上述公式分为两类破碎波高计算模型,一类是直接计算模型;另一类是联立拍岸浪波高计算模型与破碎判据,建立的间接计算模型。在此基础上,结合实验数据,对破碎波高和破碎指标进行误差分析得出,间接计算模型中,Goda提出的破碎判据效果最好,为下一步拍岸浪精细化预报以及其区域计算模型的建立提供参考。     

海南岛西岸上升流对波浪混合的敏感性研究

The coupled ocean–atmosphere–wave–sediment transport(COAWST) modeling system is employed to investigate the role of wave-mixing playing in the upwelling off the west coast of Hainan Island(WHU). Waves,tides and sea surface temperature(SST) are reproduced reasonably well by the model when validated by observations. Model results suggest the WHU is tidally driven. Further investigations indicate that inclusion of wave-mixing promotes the intensity of the WHU, making the simulated SST become more consistent with remote-sensed ones. Dynamically, wave-mixing facilitates the "outcrop" of more upwelled cold water, triggering stronger WHU and leading to a three-dimensional dynamical adjustment. From the perspective of time, wavemixing contributes to establishing an earlier tidal mixing front strong enough to generate WHU and that is, WHU may occur earlier when taking wave-mixing into consideration.     

礁冠宽度对珊瑚礁坪波浪增水影响的实验研究

通过物理模型实验研究岸礁礁冠宽度变化对礁坪上波浪增水的影响,实验采用概化的岸礁和梯形礁冠模型,在一系列规则波工况下分别测试5种不同宽度的礁冠以及无礁冠模型。实验结果表明:礁冠宽度越大,波浪破碎造成的能量衰减越剧烈;礁冠的存在使礁坪上的波浪增水增大,且礁冠宽度越大,增水值越大;增水随礁冠水深的增大而减小,并引入了一对无量纲参数合理地描述了入射波波要素对增水的影响;运用文献中基于能量守恒的理论模型进一步研究了礁冠宽度对增水的影响,并给出模型中的礁形参数与实测的礁冠相对宽度间的经验关系式;通过分析同一礁冠水深控制下,相对增水随着礁冠相对宽度的变化趋势,发现只有在礁冠充分宽的情况下礁冠水深才是控制礁坪上增水的主要因素。     

基于波形不对称性的波浪破碎指标

为了探寻波浪破碎与波形不对称性的关系,通过对1/200缓坡上波浪破碎实验研究结果的进一步分析,运用最小二乘法,拟合了波形不对称性参数与相对水深的关系,以及用波形不对称性参数表示的波浪破碎指标表达式。所得规则波的结果与Kjeldsen的深水波结果相同,而不规则波的结果比规则波的小。研究还表明,这一破碎指标与相对水深有关系,随着水深变浅,指标值增大。     

平缓岸坡上波浪破碎的实验研究

在１／２００的缓坡上进行了规则波与不规则波破碎的实验研究。在本实验条件下,分析了波形的不对称必至波浪破碎指标的影响,并以此对合田良实和Ｎｅｌｓｏｎ关于极平缓坡上规则波破碎指标的分歧作了解释。本文的研究还表明,底坡坡度ｉ、相对水深ｄ／Ｌ。及波形的不对称必至不规则波的破碎指标的影响较小。合田对规则波的破碎指标在不规则波条件下仍然可用,但系数Ａ应取为０．１５。不规则波波长与同周期按线悸理论计算之波长的比     

粗糙珊瑚岸礁礁面附近波浪增水实验研究

通过在波浪水槽中采用概化的珊瑚岸礁物理模型来研究珊瑚礁海岸附近波浪增水的变化规律,包括平均自由表面的沿礁变化以及礁坪上的最大增水值。物理模型实验分别测试了不同礁面糙率密度影响下的一系列不规则波工况。结果分析表明:礁面粗糙时礁坪上的透射波高和最大增水值均相对于礁面光滑时减小;通过两个无量纲参数分析表明光滑礁面时,礁坪上最大增水随波要素的变化规律与此前研究数据基本吻合,前人研究推荐的无量纲数■和■需考虑礁面粗糙度的影响;礁面粗糙程度不同时,礁坪上的透射波高随礁面糙率密度的增大而减小,礁坪上的最大波浪增水则随之增大;最后通过沿水深积分对波浪求平均的水平一维动量方程解释了本实验的观测现象。     

一种近岸区波浪破碎模型

从波浪破碎的能量关系入手,以紊流能量方程为基础,考虑破碎区内单个波在不同破碎阶段所提供的紊动能量强度的变化过程,提出了一种波浪破碎模式.通过将这一模型引入Boussinesq方程中,初步建立了一种近岸区波浪变形数学模型,并用波浪水槽实验资料对模型模拟波高和平均水位的情况进行了初步验证,得到了良好的结果.     

Experimental Study on the Effects of A Breakwater on Wave Field Characteristics

Studies on the possible effects of a detached breakwater on the characteristics of the wavefield are carried out experimentally.A serpentine wave generator is used to generate both uni- andmulti-directional waves.Characteristics of the wave fields analyzed here include the wave fielddirectionality,and the probability distributions of surface elevations and of the wave heights.Owing to thepresence of the breakwater,waves outside the harbour are found to be reflected with,however,concen-trated energy within the harbour entrance.In general,wave heights can be approximated with a Rayleighdistribution,with occasional deviations from the theory.This occurs more frequently for waves with high-er peak frequency values than for those with lower values both for uni-and multi-directional waves.Sur-face elevations can be approximated with the Gaussian model.although the Edgeworth's form of the typeA Gram-Charlier series expansions would yield better fits.Wave directionality is found to have nodiscernible effects on     

波浪作用下岸滩坡度对推移质输沙率影响的实验研究

对波浪作用下推移质输沙率的研究理论和实验,一般都胆建立在平底海床上波浪运动、水平底部剪切力作用的力学模式基础之上,而不考虑海床坡度引起的波浪变形、底部剪切力变化导致的向岸、离岸方向的推我质输移的差异。研究在波浪作用下坡度海床上推移质运动机理,不仅需要建立可靠的力学模式进行理论分析,而且更需要采用大量的模型实验资料来验证、完善力学模型。正是基于寻坡度海床上推移质运动机理研究的需要,本文给出了四个坡度     

Experimental Investigation of Wave Heights in A Directional Wave Field Through Image Sequences

Measurements of wave heights with image sequences from a Charged Coupled Device(CCD) camera were made. Sinusoidal, as well as unidirectional and directional, waves were used for the experiments. A transfer function was obtained by calibration of the magnitudes of the gray values of the images against the results of wave gauge measurements for directional waves. With this transfer function, wave heights for regular waves were deduced. It is shown that the average relative errors are smaller than 16% for both unidirectional and directional waves.     

Simulation of Pollutant Transport in Marmaris Bay

The circulation pattern and the pollutant transport in the Marmaris Bay are simulated by the developed three-dimensional baroclinic model. The Marmaris Bay is located at the Mediterranean Sea coast of Turkey. Since the sp ring tidal range is typically 20- 30 cm, the dominant forcing for the circulation and water exchange is due to the wind action. In the Marmaris Bay, there is sea outfall discharging directly into the bay. and that threats the bay water quality significantly. The current patterns in the vicinity of the outfall have been observed by tracking drogues which are moved by currents at different water depths. In the simulations of pollutant transport, the coliforms-counts is used as the tracer. The model provides realistic predictions for the circulation and pollutant transport in the Marmaris Bay. The transport model component predictions well agree with the results of a laboratory model study.     

降雨对波浪成长的影响实验研究

本文通过实验室实验的方法,对降雨对海面粗糙度以及风浪和涌浪成长的影响进行了初步的分析;用波面位移数据计算了海浪谱,初步讨论了降雨对波浪成长的影响。分析结果表明:在低风速时,降雨对波浪成长起抑制作用;而在高风速时,降雨对波浪成长起促进作用。其物理机制有待于进一步分析。     

Experimental Study of Wave Breaking on Gentle Slope

—An experimental study of regular wave and irregular wave breaking is performed on a gentleslope of 1:200.In the experiment,asymmetry of wave profile is analyzed to determine its effect on wavebreaker indices and to explain the difference between Goda and Nelson about the breaker indices of regu-lar waves on very mild slopes.The study shows that the breaker index of irregular waves is under less influ-ence of bottom slope i,relative water depth d/L_0 and the asymmetry of wave profile than that of regularwaves.The breaker index of regular waves from Goda may be used in the case of irregular waves, whilethe coefficient A should be 0.15.The ratio of irregular wavelength to the length calculated by linear wavetheory is 0.74.Analysis is also made on the waveheight damping coefficient of regular waves after break-ing and on the breaking probability of large irregular waves.     

Wave Attenuation and Friction Coefficient on the Coral-Reef Flat

Several sets of S4 direction-wave-current-tide meters have been deployed on the coral-reef fiat of Yongshu Reef in the sea area of Nansha Islands. Based on the observational sea wave data, the attenuation characteristics of the waves propagating on the coral reef flat, the bottom friction coefficients and the transfer of wave energy are discussed in the paper. The results show that, in the relative depths of 0. 0613- 0.0867, the wave height attenuation per unit distance of wave propagation is 22.09 %-46.56%, with an average of 31.35 % ; the wave energy, attenuation coefficient, 33.74 %- 53.22%, with an average of 43.61%. The average of the bettom friction coefficients on the coral-reef flat is 0. 1346,which is about 10 times thai on the sand or silt bottom. In the couse of propagation on the reef flat, the waves sustain more loss in high frequency than in low frequency and the spectral energy transfers to the low frequency. These results may be used for reference in island and reef engineering.     

Experimental Study of Wave Pressure on a Breakwater Pier

Test studies on the wave pressure on a breakwater pier show that the influence of transmissivewave pressure on the outside wall of the breakwater pier is considerable,when the width of the pier is notvery large.The variations of transmissive wave pressure on the breakwater pier with different widths arecompared and the relationship is obtained between relative transmitting distance b/L and wave pressurereduction factor K,which may be used in the design of similar breakwater piers.     

碟形越浪式波能发电装置越浪性能的试验研究

碟形越浪式波能发电装置是1种新型的波能发电装置,本文对其几何形状及尺寸进行了初始设计。通过对装置越浪性能的物理模型试验研究,揭示了装置越浪量与入射波要素的变化关系,得到了不同干舷高度在各入射波要素下装置的波能俘获能力。