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1.
Li Chunzhu Shi Hongda Yu Dingyong Wang Aiqun
Professor Engineering College Ocean University of Qingdao Qingdao
Lecturer Engineering College Ocean University of Qingdao Qingdao
Senior Engineer Engineering College Ocean University of Qingdao Qingdao 《中国海洋工程》1997,(1)
Standing waves are formed due to the reflection when waves meet vertical wall,thereforestrong structures are needed to keep the wall stability under the serious wave attack.For the improvementof the working condition and increase of the stability of the wall,the lower reflecting breakwaters have at-tracted close attention Reports mostly from Japanese researchers are often concerned with the wall ofcaisson equipped with open windows.In this paper a kind of hollow-pipe perforated breakwater is exam-ined which waves may partially perforate into the harbour basin.The wave in front of the wall can onlyform partial standing wave and wave force is reduced obviously.And the theoretical calculation of waveforce and analysis of wave force spectrum are all derived.Comparison between the results from theoreticalcalculation and hydraulic modeling shows reasonable agreement. 相似文献
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1 .IntroductionWavereflectionfromstructuresisanimportantfactorforthedesignofthestructures .Therehavebeenmanyresearchesonwavereflectionwithregularwavesandmonochromaticirregularwaves .Miche( 1 951 )proposedanon dimensionalMichenumberMfornormallyincidentirregularwavesconsideringwavebreakingbecauseofthedeepeningofwavesteepnessontheslopeofbreakwaters .ThereflectioncoefficientisproportionaltoM ,i.e .,Kr ∝M =4g( 2π) 5/ 2tan5/ 2 α(Hsf2p) ( 1 )wheregisthegravitationalacceleration ,Hsthesignifican… 相似文献
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Wang Jianyi
Ge Zhijin Senior Engineer River Harbour Department Nanjing Hydraulic Research Institute Nanjing 《中国海洋工程》1993,(2)
- This paper describes the design of a permeable caisson breakwater with slanting slabs (Types I and 11) and presents some preliminary experimental results, together with relevant figures and tables. Analysis is made of the reflection coefficient, transmission coefficient, acting wave pressures, water jetting at the crest of the breakwater, and wave overtopping. Experiments show conclusively that this type of breakwater has the advantages of light dead weight, good wave-absorbing performance, low coefficients of reflection and transmission, and small wave overtopping. 相似文献
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Wang Jianyi Senior Engineer River Harbour Department Nanjing Hydraulic Research Institute Nanjing 《中国海洋工程》1992,(1)
This paper describes the design of a perforated caisson breakwater and presents the results of model test. Tests with regular and irregular waves have demonstrated that the perforated caisson breakwater has the advantages of low reflection coefficient, good wave-absorbing performance, relatively small wave height in front of the breakwater, and small amount of overtopping. Analyses have been made of the coefficient of reflection, wave height in front of the breakwater, and wave overtopping. Relevant figures and tables are presented for reference. 相似文献
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Lao Guosheng Feng Hong Associate Professor Dalian University of Technology Dalian Postgraduate Dalian University of Technology Dalian 《中国海洋工程》1992,(4)
- In this paper, the theoretical calculation of floating breakwater performance in regular waves with arbitrary wave direction is discussed. Under the hypothesis of linearized system and applying the strip theory, we can solve the boundary condition problems of diffraction potential and radiation potential. Introducing the asymptotic expression of the wave velocity potential at infinity and using wave energy conservation, we can separately calculate the transmitted waves generated by the sway, heave and roll motion of the floating breakwater and by the fixed breakwater. Finally, we define the amplitude ratio of the transmitted wave to the incident wave as the transmitted wave coefficient CT which describes the floating breakwater effectiveness. Two examples are given and the theoretical results obtained by the present method agree well with experimental results. 相似文献
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潜堤对波浪传播变形的物理模型试验研究 总被引:1,自引:0,他引:1
以不可渗透光滑潜堤为研究对象,基于波浪水槽试验,分析了规则波和不规则波通过淹没梯形潜堤时的波浪外部形态变化以及内部能量变化规律。探讨了不同波浪要素(周期、波高、淹没水深)对潜堤附近波高影响的变化规律。同时,探究了潜堤斜坡坡度、堤顶淹没水深对波浪频谱在频域分布的影响。研究结果表明:当波浪通过潜堤时,波浪主频能量衰减,波浪能量由低频向高频移动;潜堤斜坡坡度越大、堤顶水深越小,波浪主频能量衰减越剧烈;波浪通过潜堤后高频波能量占潜堤次生波能量的1%~30%。 相似文献
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本文提出了一种倾斜挡浪板式桩基透空型防波堤,通过物理模型试验对规则波作用下防波堤的消浪性能进行了研究。试验中观测了桩基透空型防波堤迎浪侧和背浪侧波面的变化过程,探讨了不同入射波浪条件下防波堤挡浪板的开孔率ε和布置形式B对其消浪性能的影响,分析了防波堤的反射系数Kr、透射系数Kt以及波能耗散系数Kd随着相对波高H/D和相对堤宽W/L的变化关系,并从波浪能量分布的角度分析此种防波堤的消浪机理。研究结果表明,单层挡浪板的开孔率自30%降低至10%,平均透射系数可减小约24.3%,平均耗散系数可增长约12.8%;双层挡浪板防波堤的反射系数取决于前排挡浪板的开孔率,透射系数取决于挡浪板组合中的最小开孔率。 相似文献
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A series of regular and irregular wave experiments are conducted to study the reflective and transmitting performances of quarter circular breakwater (QCB) in comparison with those of semi-circular breakwater (SCB). Based on regular wave tests, the reflection and transmission characteristics of QCB are analyzed and a few influencing factors are investigated. Then, the wave energy dissipation as wave passing over the breakwater is discussed based on the hydraulic coefficients of QCB and SCB. In irregular wav... 相似文献
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The scaled boundary finite element method (SBFEM) is a novel semi-analytical technique combining the advantage of the finite element method (FEM) and the boundary element method (BEM) with its unique properties. In this paper, the SBFEM is used for computing wave passing submerged breakwaters, and the reflection coeffcient and transmission coefficient are given for the case of wave passing by a rectangular submerged breakwater, a rigid submerged barrier breakwater and a trapezium submerged breakwater in a constant water depth. The results are compared with the analytical solution and experimental results. Good agreement is obtained. Through comparison with the results using the dual boundary element method (DBEM), it is found that the SBFEM can obtain higher accuracy with fewer elements. Many submerged breakwaters with different dimensions are computed by the SBFEM, and the changing character of the reflection coeffcient and the transmission coefficient are given in the current study. 相似文献
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PAN Shaohua XIAQiyi LIN Shiqing XU Lunhuan
Professor Dept. of Coastal Engineering College of Harbour Waterway Coastal Engineering Hohai University Nanjing P. R. China.
Senior Engineer Dept. of Coastal Engineering College of Harbour Waterway Coastal Engineering Hohai University Nanjing P. R. China.
Senior Engineer Fujian Province Ports Shipping Administration Bureau Fuzhou P. R. China. 《中国海洋工程》1999,(2)
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. 相似文献
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直立式防波堤堤头在斜向波浪作用下波浪力的计算在现行的技术规范中尚属空白。通过物理模型试验给出了堤头结构设计所需的波压分布图,指出了波浪入射方向和地形对堤头所受波浪力的贡献有时可以超过波高和波周期,根据现行规范按波浪正向入射计算堤头所受的波浪力偏于安全。 相似文献
13.
Interaction Between Waves and A Comb-Type Breakwater 总被引:2,自引:1,他引:2
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
14.
对梳状沉箱防波堤的波浪反射特征进行研究。在对梳状沉箱防波堤非线性消耗波能机理分析基础上,采用阻抗分析方法,导出一组所有参数都是事先知道的、完全封闭的波反射系数公式。 相似文献
15.
Quarter circular breakwater (QCB) is a new-type breakwater developed from senti-circular breakwater (SCB). The superstructure of QCB is composed of a quarter circular front wall, a horizontal base slab and a vertical rear wall. The width of QCB' s base slab is about half that of SCB, which makes QCB suitable to be used on relatively finn soil foundation. The numerical wave flume based on the Reynolds averaged Navier-Stokes equations for impressible viscosity fluid is adopted in this paper to simulate the hydraulic performances of QCB. Since the geometry of both breakwaters is similar and SCB has been studied in depth, the hydraulic performances of QCB are given in comparison with those of SCB. 相似文献
16.
Hsien-KuoCHANG Jin-ChengLIOU 《中国海洋工程》2004,18(3):371-380
This investigation examines long wave reflection and transmission induced by a sloping step. Bellman and Kalaba‘s (1959) invariant imbeddlng is introduced to find wave reflection. An alternative method matching both the surface elevation and its surface slope of each region at the junction is applied to the determination of wave reflection and transmission.The proposed methods are compared with the accurate numerical results of Porter and Porter (2000) and those of Mei (1983) for a vertical step. The wave reflection obtained for a mildly sloping step differs significantly from the result of Mei. The wave reflection is found to fluctuate owing to wave trapping for the ntild sloping step. The height and the face slope of the step are important for determining wave reflection and transmission coefficients. 相似文献
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1 .IntroductionTremendousdevelopmentofinternationaltradeandseatransportationhastakenplacesincethe1 980s.Duringthesameperiodoftime ,harbortransportationincreasedmarkedly ,resultinginthede teriorationofwaveconditionsinharbors .Reducingwavedamagetoportandmarine… 相似文献
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