Interaction Between Waves and A Comb-Type Breakwater   总被引：2，自引：1，他引：2  

DONG  Guo-hai 《中国海洋工程》2003,17(4):517-526

The characteristics of wave transmission, reflection and energy dissipation of comb-type caisson breakwaters are studied through laboratory physical model tests. Regular and irregular waves, with a wide range of wave heights and periods and a constant water depth, are considered. Different dimensions of each portion of the comb-type caisson breakwater are tested. Empirical formulae for calculating the reduction coefficient k, which is the ratio of horizontal wave force on unit length of the comb-type breakwater to that on unit length of the vertical wall breakwater, and for calculating the reflection coefficient of waves k, are obtained from the measurements. The comb-type caisson breakwater has been found to be very efficient in dissipating incident wave energy and in reducing wave reflection, and has already been used for the construction of an island breakwater in the Dayao Bay of Dalian Port, Liaoning Province, China. Compared with the cost of a common caisson breakwater, about 24. 5% of the investm  相似文献   

Wave Attenuation Performance and the Influencing Factors of A Lower Arc-Plate Breakwater     

LI Xue-yan  WANG Qing  YOU Zai-jin  GUO Wei-jun  ZHANG Jun-bin  ZHAN Chao  ZHANG Zhi-chen  WANG Li-xue  LI Qin 《中国海洋工程》2020,(1):89-98

Comprehensive experimental and numerical studies have been undertaken to investigate wave energy dissipation performance and main influencing factors of a lower arc-plate breakwater. The numerical model, which considers nonlinear interactions between waves and the arc-plate breakwater, has been constructed by using the velocity wave- generating method, the volume of fluid (VOF) method and the finite volume method. The results show that the relative width, relative height and relative submergence of the breakwater are three main influencing factors and have significant influence on wave energy dissipation of the lower arc-plate open breakwater. The transmission coefficient is found to decrease with the increasing relative width, and the minimum transmission coefficient is 0.15 when the relative width is 0.45. The reflection coefficient is found to vary slightly with the relative width, and the maximum reflection coefficient is 0.53 when the relative width is 0.45. The transmission and reflection coefficients are shown to increase with the relative wave height for approximately 85% of the experimental tests when the relative width is 0.19 0.45. The transmission coefficients at relative submergences of 0.04, 0.02 and 0 are clearly shown to be greater than those at relative submergences of 0.02 and 0.04, while the reflection coefficient exhibits the opposite relationship. After the wave interacts with the lower arc-plate breakwater, the wave energy is mainly converted into transmission, reflection and dissipation energies. The wave attenuation performance is clearly weakened for waves with greater heights and longer periods.  相似文献   

A study of spar buoy floating breakwater     

Nai-Kuang Liang  Jen-Sheng Huang  Chih-Fei Li 《Ocean Engineering》2004,31(1):43-60

A floating breakwater produces less environmental impact, but is easily destroyed by large waves. In this paper, the spar buoy floating breakwater is introduced with a study on the wave reflection and transmission characteristics and mooring line tension induced by the waves. Mei (The Applied Dynamics of Ocean Surface Waves, Wiley, New York (1983) 740 p) proposed a theoretical solution for the reflection and transmission coefficients as the wave propagates through a one-layer slotted barrier. For a multiple-layer fence system, the analytical solution is proposed linearly. The results show that the theoretical computations agree well with the experimental trends. For a multiple-layer fence system, the transmission coefficients become maximal as the layer spacing to wavelength ratio moves to 1/2. Conversely, the coefficients become minimal, as the ratio moves to 0.3. To estimate the maximum tension of the mooring line, both numerical calculations and laboratory experiments were executed. The numerical calculation results were similar to the experimental results.  相似文献   

聚焦波作用下透水潜堤消波特性数值模拟研究     

徐瑶瑶  屈科  黄竞萱  蓝港芸  刘铁威  温博浩 《海洋学报》2022,44(11):121-132

基于非静压数值计算模型,本文系统研究了聚焦波作用下透水潜堤的消波特性,通过设置合理的计算工况,详细分析了波高、堤顶水深、谱峰周期、孔隙率以及堤顶宽度5种因素对透水潜堤消波特性的影响。与此同时,本文将透水潜堤的计算结果同不透水潜堤的计算结果进行了对比分析。计算结果表明:透水潜堤对聚焦波的消减作用要强于不透水潜堤,从而说明,透水潜堤能更有效地降低畸形波对海岸基础设施的影响;波高和堤顶水深是影响潜堤消波特性的重要因素,随入射波高增加、堤顶水深减小,透水潜堤对波浪的消减作用逐渐增强。透水潜堤对长周期波浪的消波效果较差。在本文考虑的孔隙率范围内,孔隙率越大,透水潜堤消波效果越好;当孔隙率为0.4,堤顶宽度为0.612 5 m时,透水潜堤可消减54%的入射波能,比不透水潜堤对入射波能的消减增加36.1%。本文研究结果可为进一步认识透水潜堤的消波特性和海岸防护工程设计提供相应的参考。  相似文献   

直立式防波堤口门区海啸局部冲刷规律实验研究     

陈杰  段自豪  崔懿秋  管喆  高清洋  曹城 《海洋通报》2017,36(4):475-480

海啸作为世界上最严重的自然灾害之一,其巨大的破坏力使得近海建筑物遭受了严重的损害。基于波浪水槽实验,开展海啸波作用下不同口门距离的防波堤局部冲刷机理实验研究。实验结果表明,在海啸波越顶水流产生的水跌以及海啸波通过防波堤口门时产生的扰流共同作用下,口门中心线处产生明显的局部冲刷坑,随着口门距离的增加,防波堤局部冲刷先加剧后减弱。建立防波堤局部最大冲刷深度与海啸波波高、防波堤宽度及出水高度、口门间距的关系式,揭示了最大局部冲刷深度与海啸波波高、防波堤尺寸、口门距离的内在关系。  相似文献   

不规则波作用下垂直挡板式透空堤透浪系数试验研究     

邵杰  陈国平  严士常  杨嵚 《海洋工程》2016,34(1):50-57

垂直挡板式透空堤作为一种新型的透空式防波堤结构,通过将挡浪板垂直设置于波能最集中的水体表层来消减波浪,透浪系数是其最关键的指标。通过物理模型试验,分析不规则波作用下入射波高、波周期、挡板相对入水深度、相对堤宽、相对挡板超高、相对面板超高等因素对垂直挡板式透空堤透浪系数的影响规律,并在Wiegel公式的基础上拟合了垂直挡板式透空堤透浪系数的计算公式。可作为今后类似透空式防波堤结构透浪系数的近似估算,具有一定的参考价值。  相似文献   

圆弧板透空式防波堤消波性能试验研究   总被引：1，自引：1，他引：0  

潘春昌  王国玉  任冰  王永学 《海洋工程》2014,32(4):33-40

提出了一种由多层圆弧板组成的新型透空式防波堤结构,并对其在二维规则波浪作用下的消波性能进行了物理模型试验研究。在不同入射波高条件下,对圆弧板和水平板透空结构的消波性能进行了比较分析,探讨了圆弧板间距和层数对圆弧板透空式结构消波性能的影响。研究结果表明,圆弧板透空式结构的消波效果优于水平板式透空结构,在相对宽度为0.2时,可以使透射系数达0.5以下。随着圆弧板间距从0.15 m减小到0.05 m时,消波效果逐步提升,而圆弧板的层数对结构的消波性能也有一定影响。  相似文献   

Experiments on wave transmission coefficients of floating breakwaters   总被引：1，自引：0，他引：1  

G.H. Dong  Y.N. Zheng  Y.C. Li  B. Teng  C.T. Guan  D.F. Lin 《Ocean Engineering》2008,35(8-9):931-938

To find a simple, inexpensive, and effective type of floating breakwater for deep-sea aquaculture, we studied three types of structures: the single box, the double box, and the board net. We conducted two-dimensional physical model tests in a wave-current flume in the laboratory to measure the wave transmission coefficients of the three types of breakwaters under regular waves with or without currents. Based on the initial comparison of the wave transmission coefficients, we proposed the use of the board-net floating breakwater for use with fish cages; we then conducted detailed experiments to examine how wave transmission coefficients are affected by several factors, including the width of the board, the row number of the net, the rigidity of the board, and the current velocity. The experimental results show that the board-net floating breakwater, which is a simple and inexpensive type of structure, can effectively protect fish and fish cages and may be adopted for aquaculture engineering in deep-water regions.  相似文献   

Reflection of irregular waves from perforated-wall caisson breakwaters     

《Coastal Engineering》2001,44(2):141-151

An analytical model has been developed that predicts the reflection of irregular waves normally incident upon a perforated-wall caisson breakwater. To examine the predictability of the developed model, laboratory experiments have been conducted for the reflection of irregular waves of various significant wave heights and periods impinging upon breakwaters having various wave chamber widths. For frequency-averaged reflection coefficients, though the overall agreement is fairly good between measurement and calculation, the model somewhat over-predicts the reflection coefficients at larger values, and under-predicts at smaller values. The model also underestimates the energy loss coefficients as wave reflection becomes larger. These differences occur because the model neglects the evanescent waves near the breakwater, which increase the energy loss at the perforated wall. The frequency-averaged reflection coefficient shows a minimum when the wave chamber width is approximately 0.2 times the significant wavelength, and it decreases with increasing wave steepness. Finally, it is shown that the reflection of irregular waves from a perforated-wall caisson breakwater depends on the wave frequency, so that the reflected wave spectrum shows a frequency dependent oscillatory behavior.  相似文献   

半圆型防波堤的水力特性研究   总被引：5，自引：1，他引：4  

俞聿修  张宁川  饶永红 《海洋工程》1999,17(4)

采用不规则波浪试验,研究了半圆型防波堤的水力特性及堤上波力随各主要影响因素的变化规律。指出必须分别按出水堤或淹没堤计算堤上的波力,前者可用改进的合田公式;对于淹没堤,文中建议了计算波力的方法。  相似文献   

Numerical investigation on the dynamics of a vertical wall defenced by an offshore breakwater   总被引：1，自引：0，他引：1  

M.G. Muni Reddy  S.A. Sannasiraj  R. Natarajan   《Ocean Engineering》2007,34(5-6):790-798

The numerical and experimental investigations on the performance of an offshore-submerged breakwater in reducing the wave forces and wave run-up on vertical wall are presented. A two-dimensional finite-element model is employed to study the hydrodynamic performance of the submerged breakwater under the action of regular and random waves. The numerical prediction has been supported with experimental measurements. The wave forces and wave run-up on the vertical wall were measured for different breakwater configurations. The applicability of linear theoretical model in the prediction of wave forces on the wall by a submerged breakwater has been discussed.  相似文献   

Wave interaction with T-type breakwaters   总被引：1，自引：0，他引：1  

S. Neelamani  R. Rajendran 《Ocean Engineering》2002,29(2):151-175

The wave transmission, reflection and energy dissipation characteristics of partially submerged ‘T'-type breakwaters (Fig. 1) were studied using physical models. Regular and random waves, with wide ranges of wave heights and periods and a constant water depth were used. Five different depths of immersions of the ‘T'-type breakwater were selected. The coefficient of transmission, K_t, coefficient reflection, K_r, were obtained from the measurements and the coefficient of energy loss, K_l is calculated using the law of conservation of energy. It is found that the coefficient of transmission generally reduces with increased wave steepness and increased relative water depth, d/L. This breakwater is found to be effective closer to deep-water conditions. K_t values less than 0.35 is obtained for both normal and high input wave energy levels, when the horizontal barrier of the T type breakwater is immersed to about 7% of the water depth. This breakwater is also found to be very efficient in dissipating the incident wave energy to an extent of about 65% (i.e. K_l>0.8), especially for high input wave energy levels. The wave climate in front of the breakwater is also measured and studied.