Experimental Study on the Armor Grate Plate of Sloping Breakwater Under the Action of Irregular Waves

The irregular wave experiment on the stability of the Grate Plate was carried out in the lightof the wind wave spectrum recently advanced by Prof.Wen Shengchang.The stability formulas of GP un-der the action of irregular waves were procured.Comparisons between the formulas obtained and those ofGP under regular waves advanced by the first author in 1993 showed a coincident result.     

Hydrodynamic Coefficients for Grouping Piles Under the Action of Irregular Waves

-The hydrodynamic coefficients for each of two piles and three piles in both side-by-side arrangement and tandem arrangement under the action of irregular waves are experimentally investigated. These coefficients vary with the KC number, the relative pile spacing, the number of piles and the pile location, and their relationships are presented in this paper. They can be used in Morison Equation and other equations to calculate directly the in-line wave forces and the transverse forces on each pile in array.     

Experimental Researches on Reflective and Transmitting Performances of Quarter Circular Breakwater Under Regular and Irregular Waves

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...     

Theoretical Model and Random Simulation for Nonlinear Interaction of Irregular Waves with Vertical Wall

According to the theoretical solutions for the nonlinear three-dimensional gravity surface waves and their interactions with vertical wall previously proposed by the lead author, in this paper an exact second-order random model of the unified wave motion process for nonlinear irregular waves and their interactions with vertical wall in uniform current is formulated, the corresponding theoretical nonlinear spectrum is derived, and the digital simulation model suitable to the use of the FFT (Fast Fourier Tansform) algorithm is also given. Simulations of wave surface, wave pressure, total wave pressure and its moment are performed. The probability properties and statistical characteristics of these realizations are tested, which include the verifications of normality for linear process and of non-normality for nonlinear process; the consistances of the theoretical spectra with simulated ones; the probability properties of apparent characterstics, such as amplitudes, periods, and extremes (maximum and minimum, positive and negative extremes). The statistical analysis and comparisons demonstrate that the proposed theoretical and computing models are realistic and effective, the estimated spectra are in good agreement with the theoretical ones, and the probability properties of the simulated waves are similar to those of the sea waves. At the same time, the simulating computation can be completed rapidly and easily.     

Numerical Simulation of Waves Interaction with A Submerged Horizontal Twin-Plate Breakwater

The numerical investigation of regular waves interacting with a submerged horizontal twin-plate breakwater is presented in this paper. A numerical model with an absorbing wave-maker is established based on the VOF method. The validity of the model is verified by experimental results. Comparisons between the numerical and experimental results show that both the water surface profiles and the wave-induced pressures can be modeled accurately. Wave deformation over the breakwater,water particle velocities aroun...     

Experimental Study on Local Scour Around A Large Circular Cylinder Under Irregular Waves

1 .IntroductionWiththedevelopmentofexploitationofmarineresources ,theconstructionofoffshorestructuresdevelopsrapidly ,suchasmarineoilplatforms ,deep waterbreakwaters ,marinebridges ,largehar bors,etc .Thesestructureswillchangesurroundingwaveandcurrentconditionsandleadtolocalscourofseabed ,resultinginstructuraldamage .Therefore ,localscouraroundmarinestructuresaswellastheirprotectionhasdrawnmuchattentionfromrelativeengineeringfields .Manyscholarshaveconduct edtheoreticalanalysisandexperimentals…     

Numerical Simulation of Multi-Directional Random Seas

Multi-directional irregular waves are simulated on the basis of the given directional spectrum using a double summation model, a single direction per frequency model and a single summation model. Their results are compared. It is shown that the single direction per frequency model proposed in this paper can generate a realistic wave field. The effects of the model parameters on the simulated results are also studied in this paper and corresponding suggestions are given.     

Response Analysis of Tension-Based Tension Leg Platform Under Irregular Waves

Tension Leg Platform (TLP) is a hybrid structure used as oil drilling and production facility within water depths of 1200 m. The extension of this TLP concept to deeper waters is a challenge and warrants for some innovative design concepts. In this paper, a relatively new concept of TLP which is christened as Tension-Based Tension Leg Platform (TBTLP) and patented by Srinivasan (1998) has been chosen for study. Response analysis of TLP with one tension base under irregular waves for three different sea states has been performed using hydrodynamic tool ANSYS? AQWA?. Results are reported in terms of RAOs, response spectrums for surge, heave and pitch degrees of freedom from which spectral statistics have been obtained. The statistics of TBTLP have been compared with TLPs (without tension base) for two different water depths to highlight the features of the new concept. The effect of viscous damping and loading effects on the RAOs are also investigated.     

波浪谱形对不规则波数值模拟的影响

通过数值模拟分析了波浪谱形对不规则波浪数值模拟结果的影响.采用不同参数的JONSWAP谱模拟入射波要素,基于抛物型缓坡方程模拟不规则波浪的传播,分析了波浪谱形状对波浪数值模拟结果的影响.结果表明,采用抛物型缓坡方程模拟不规则波浪时,入射波浪谱形对模拟结果影响不明显;但由于模型中非线性项的影响,采用不规则波模拟的波高分布和采用规则波模拟的结果略有差别.     

Impact Pressure of Incident Regular Waves and Irregular Waves on the Subface of Open-Piled Structures

1 .IntroductionInrecentyears,theimpactloadsactingonthesuperstructureofopen piledwharfs,shoretres tles,oildrillingplatforms ,etc .,havebecomeanimportantsafetyissueinoffshoreengineering .Owingtotheeffectofseabedsubsidenceandtheoccurrenceofextremestormconditionsthatexceedpriorpre dictions,theclearanceofthesuperstructuresofsomemarinestructuresmaybeinsufficient.So ,whenwavesoflargecrestspropagatebeneaththestructure ,itsundersidewillbesubjectedtoimpactloadsofconsiderablemagnitudeswhichmaycausethesup…     

Wave Breaking Phenomena of Irregular Waves Combined with Opposing Current

- Experimental study and theoretical analysis show that the critical value of relative wave height (H/ d)b given by Goda and the critical wave steepness (H/ L)b given by Michell and Miche can be adopted as the spilling breaking indices of regular waves. According to the same principle, a systematic theoretical analysis and experiment of irregular waves have been done by the authors in order to solve the breaking problem of irregular waves. It is indicated that the authors' method for determining wave breaking of regular waves can also be used for irregular waves.     

Computation of Diffraction of Irregular Waves Behind Single Jetty

- This paper presents a calculation method for the diffraction of both regular waves and irregular waves of the single directional frequency spectrum behind a single jetty with a theoretical analysis, which has been confirmed through the model experiments, derives a method of computing the diffracted irregular waves behind the single jetty with the theoretical analysis on the basis of computation of the field data and gives the formulas and the figures of the computation of wave diffractions behind the vertical wall or mound single jetties.     

Computation of Diffraction of Irregular Waves Behind Double Jetty

The coefficient of deffraction of regular waves behind the double jetty has been computed in this paper at first by using the singularity distribution method. The model tests conducted for diffraction of irregular waves with a unidirectional frequency spectrum have confirmed good agreement between the data measured in experiments and the results computed by the singularity distribution method plus the linear superposition method for the energy of component waves in the directional frequency spectra. Therefore, this technique for component waves in the directional spectra has been further used to compute diffraction of irregular waves of multidirection, including the employment of a directional distribution function of the cos2 type, as well as the Bretschneider-Misuyann frequency spectrum.     

Numerical Simulation of Nonlinear Three Dimensional Waves in Water of Arbitrary Varying Topography

—The numerical simulation is based on the authors＇high-order models with a dissipative termfor nonlinear and dispersive wave in water of varying depth.Corresponding finite-difference equations andgeneral conditions for open and fixed natural boundaries with an arbitrary reflection coefficient and phaseshift are also given in this paper.The systematical tests of numerical simulation show that the theoreticalmodels,the finite-difference algorithms and the boundary conditions can give good calculation results forthe wave propagating in shallow and deep water with an arbitrary slope varying from gentle to steep.     

Numerical Simulation on Oscillation-Sliding-Uplift Rock Coupled Motion of Caisson Breakwater Under Wave Excitation

Corresponding to the sliding and the overturning failure, the elementary motion modes of caisson breakwater include the horizontal-rotational oscillation coupled motion, the horizontal sliding-rotational oscillation coupled motion, the horizontal vibrating-uplift rocking coupled motion, and the horizontal sliding-uplift rocking coupled motion. The motion mode of a caisson will transform from one to another depending on the wave forces and the motion behaviors of the caisson. The numerical models of four motion modes of caisson are developed, and the numerical simulation procedure for joint motion process of various modes of caisson breakwater under wave excitation is presented and tested by a physical model experiment . It is concluded that the simulation procedure is reliable and can be applied to the dynamic stability analysis of caisson breakwaters.     

Numerical Simulation on Oscillation-Sliding-Uplift Rock Coupled Motion of Caisson Breakwater Under Wave Excitation

Corresponding to the sliding and the overturning failure, the elementary motion modes of caisson breakwater include the horizontal-rotational oscillation coupled motion, the horizontal sliding-rotational oscillation coupled motion, the horizontal vibrating-uplift rocking coupled motion, and the horizontal sliding- uplift rocking coupled motion. The motion mode of a caisson will transform from one to another depending on the wave forces and the motion behaviors of the caisson. The numerical models of four motion modes of caisson are developed, and the numerical simulation procedure for joint motion process of various modes of caisson breakwater under wave excitation is presented and tested by a physical model experiment. It is concluded that the simulation procedure is reliable and can be applied to the dynamic stability analysis of caisson breakwaters.     

近岸海浪模式在中国东海台风浪模拟中的应用--数值模拟及物理过程研究

较为详细地介绍了基于能量平衡方程的第三代近岸海浪数值模式SWAN（Simulation Waves Nearshore）及其包含的物理过程（风生浪、底摩擦、白浪耗散、深度诱导波破碎、非线性波－波相作用等），并利用该模式对影响杭州湾－长江口沿岸海域的一次台风浪过程进行了模拟研究：模式所需风场由藤田台风风场模型嵌入对应台风特征等压线，并对相应时段的NCAR／NCEPT资料、单站资料进行同化后提供；利用自嵌套的方式提供波谱边界条件；模式模拟的结果与实际海浪观测资料相符较好，在此基础上，研究了底摩擦、深度诱导波破碎、三波相互作用等物理过程联合对近岸台风浪的影响，初步认识了它们在近岸台风浪生成、传播过程中的重要作用。     

莺歌海三莺村岸段人工沙滩工程岸线数值模拟以及模型的验证方

以乐东莺歌海三莺村岸段人工沙滩工程为例,其完工1年后的岸线监测结果,表明需要进一步对人工沙滩后的海滩岸线演变进行研究分析。通过GENESIS岸线演变模型模拟人工沙滩后的岸线变化,并尝试采用3种方法对模型进行验证。经过验证后,对人工沙滩工程后1年、3年、5年岸线变化进行了模拟分析。研究结果表明:GENESIS岸线演变模型对于包围型(拦沙堤和离岸堤结合方式)人工沙滩工程是适用的。工程完工1年后,补沙岸线形成了侵淤变化的凹凸弯曲岸线,侵淤幅度不大,5年后侵淤幅度变缓,开始逐渐趋于平衡。据此,也为人工沙滩后期的养护、补沙防护工作起到重要的参考作用。