球坐标系下MASNUM海浪数值模式的建立及其应用

为开展海浪对海洋上混合层的搅拌混合作用及其对海气界面通量的影响等研究,在LAGFD WAM区域海浪数值模式基础上建立了球坐标系下的全球海浪数值模式.重点导出了球坐标系下的海浪能量谱平衡方程及其复杂特征线方程,该组方程包含了背景流场对波动传播的调整、波动沿大圆传播的折射等.数值积分则采用复杂特征线嵌入计算格式.初步数值模拟结果表明,该海浪全球数值模式能够较为精确地刻画海浪的动力过程.     

LAGFD-Ⅱ区域性海浪数值模式及其应用 Ⅱ.特征线嵌入网格计算方法

给出了LAGFD-Ⅱ区域性海浪数值预报模式的数值计算格式和特征线嵌入网格计算方法,并给出了与WAM模式对比的计算结果和渤海寒潮浪模拟与实测数据的比较,结果是相当一致的。     

LAGFD-WAM海浪数值模式 Ⅱ.区域性特征线嵌入格式及其应用

详细地讨论了非线性源函数的参数化计算方法和模式的隐格式处理,所设计的特征线嵌入格式具有很强的物理意义,解决了时间步长与空间步长的匹配问题,既节省计算时间,又能保证计算结果的精确度。标准风场下的计算结果显示,LAGFD-WAM模式与WAM模式相比有较大改进。LAGFD-WAM模式的台风浪后报结果能很好地与实测资料符合,说明本模式完全适用于区域性海浪数值预报和后报研究。     

格式耗散对WAM海浪模式预报结果的影响

分析了ＷＡＭ海浪模式中计算谱传播的一阶迎风格式的特性，导出了二阶精度的二维ＱＵＩＣＫＥＳＴ格式，利用它计算海浪能谱的传谱，研究了格式耗散对预报结果的影响。     

特征线计算格式下共轭方程两种导出途径的比较

共轭方程的导出是建立资料同化模型的关键，其导出方式有两种途径：AFD形式与FDA形式。在特征线计算格式基础上针对一类较广泛海洋动力控制方程分析了其两种共轭方程（AFD形式与FDA形式）之间的关系，并将理论结果应用于波谱共轭方程的讨论。     

运动坐标系下海浪数值模拟

以运动坐标系中的海浪谱为靶谱应用静止坐标系中随机波面的模拟方法－－线性叠架法和线性过滤法模拟均速运动坐标系听随机波面,给出了两种方法的原理及模拟手续。通过模拟实验发现,在高速运动的坐标系中线性叠架法优于线生过滤法,在低速情形,线性过滤法好于线性叠加法,并在模拟技术上给出了各参数的选取方法。     

琉球群岛海域海浪数值计算地形处理效应及试验分析

针对琉球群岛海域内多岛屿复杂地形对海浪数值计算的特殊影响,发展一种综合利用水深数据和高分辨率海岸线数据优化计算网格且引入次网格地形效应的方法,并利用WAVEWATCH-Ⅲ模式进行连续1个月的数值模拟试验。结果表明:采用该方法后,在计算网格分辨率上,充分考虑了海岸和多岛屿地形对海浪传播的作用和多岛屿的次网格效应,数值计算结果有明显改善。     

LAGFD-Ⅱ区域性海浪数值模式及其应用Ⅰ.海浪数值模式

给出了LAGFD-Ⅱ区域性海浪数值模式,详细地导出了波数空间中的复杂特征线方程。在模式中除了含有一般的各项源函数项之外,我们还给出了波、流相互作用源函数,并对非线性相互作用源函数作了一种简化处理,模式的数值计算取得了令人满意的结果。     

海浪单过程的数值模拟

本文以离散付里叶变换手段数值模拟海浪过程。对海浪单过程的模拟提出三种具体模式，并介绍了模拟的实现方法。以我国1966年提出的海浪谱为靶谱，在DTS-6电子计算机上实现，给出了模拟波面及谱曲线。比较靶谱及模拟谱表明，以m=400个子波叠加进行模拟时，模式及实现方法是满意的。     

Numerical Modeling of Wave Diffraction-Refraction in Water of Varying Current and Topography

—A numerical model for wave diffraction-refraction in water of varying current and topogra-phy is proposed,and time-dependent wave mild-slope equation with a dissipation term and correspondingequivalent governing equations are presented.Two different expressions of parabolic approximations forthe case of the absence of current are also given and analyzed.The influence of current on the results ofsimulation of waves is discussed.Some examples show that the present model is better than others in simu-lating wave transformation in large water areas.And they also show that the influence of current shouldbe taken into account,on numerical modeling of wave propagation in water of strong current and coastalareas,otherwise the modeling results will be largely distorted.     

任意水深变化水域非线性波数值模拟

为了较为准确地计算沙质海岸沿岸输沙率,基于网格模型建立沙质海岸波浪的传播变化模型,根据求得的波高和波向分布特征,并考虑辐射应力等,计算波生流的分布。并在此基础上通过波浪最大底部轨道速度和沿岸流的分布特点,建立估算破波带内各网格单元上沿岸输沙率的分布模型。     

青岛浮山湾数值化海区建立的研究--浮山湾波浪模型的建立

在考虑了地形变化,水域开挖,建筑物的掩护,码头和防波堤的反射等对波浪影响的基础上,建立了青岛浮山湾海区波浪模型.计算网格采用矩形网格,为了减少误差,保证计算的精度,计算中均采用正向入射,岸滩按全吸收边界考虑.由模型计算得出各计算点在不同水位和浪向时50年一遇的比波高和波高值.为奥运赛场的建设规划提供了基础依据.     

Verification of A Numerical Harbour Wave Model

A numerical model for wave propagation in a harbour is verified by use of physical models.The extended time-dependent mild slope equation is employed as the governing equation,and the model is solved by use of ADI method containing the relaxation factor.Firstly,the reflection coefficient of waves in front of rubble-mound breakwaters under oblique incident waves is determined through physical model tests,and it is regarded as the basis for simulating partial reflection boundaries of the numerical model.Then model tests on refraction,diffraction and reflection of waves in a harbour are performed to measure wave height distribution.Comparative results between physical and numerical model tests show that the present numerical model can satisfactorily simulate the propagation of regular and irregular waves in a harbour with complex topography and boundary conditions.     

Wave Numerical Model for Shallow Water

The history of forecasting wind waves by wave energy conservation equation is briefly des-cribed.Several currently used wave numerical models for shallow water based on different wave theoriesare discussed.Wave energy conservation models for the simulation of shallow water waves are introduced,with emphasis placed on the SWAN model,which takes use of the most advanced wave research achieve-ments and has been applied to several theoretical and field conditions.The characteristics and applicabilityof the model,the finite difference numerical scheme of the action balance equation and its source termscomputing methods are described in detail.The model has been verified with the propagation refractionnumerical experiments for waves propagating in following and opposing currents;finally.the model is ap-plied to the Haian Gulf area to simulate the wave height and wave period field there,and the results arecompared with observed data.     

Numerical Simulation of Wave Height and Wave Set-Up in Nearshore Regions

Based on the time dependent mild slope equation including the effect of wave energy dissipation, an expression for the energy dissipation factor is derived in conjunction with the wave energy balance equation, and then a practical method for the simulation of wave height and wave set-up in nearshore regions is presented. The variation of the complex wave amplitude is numerically simulated by use of the parabolic mild slope equation including the effect of wave energy dissipation due to wave breaking. The components of wave radiation stress are calculated subsequently by new expressions for them according to the obtained complex wave amplitude, and then the depth-averaged equation is applied to the calculation of wave set-up due to wave breaking. Numerical results are in good agreement with experimental data, showing that the expression for the energy dissipation factor is reasonable and that the new method is effective for the simulation of wave set-up due to wave breaking in nearshore regions.     

Numerical Model of Cnoidal Wave Flume

The volume of fluid(VOF)method is used to set up a wave flume with an absorbing wavemaker of cnoidal waves.Based on the transfer function between wave surface and paddle velocity obtained bythe shallow water wave theory,the velocity boundary condition of an absorbing wave maker is introduced toabsorb reflected waves that reach the numerical wave maker.For H/d ranging from 0.1 to 0.59 and T(g/d)~(1/2)from 7.9 to 18.3,the parametric studies have been carried out and compared with experiments.     

Numerical Analysis of Wave Forces on Arbitrarily Shaped Multi-Pillars Over Varying Topography

The modified hybrid element method (MHEM) is utilized to predict and analyze wave forces on arbitrarily shaped multiple bodies. This method can be applied to waves of all water depths, i. e. shallow, intermediate, and deep waters, on slowly varying seabed. The MHEM employs the ICCG method to save CPU and storage, thus the computation of wave forces for large multi-body systems can be carried out on microcomputers. Numerical results of the present method are compared with experimental data and other solutions. It is shown that the MHEM provides more accurate solutions of the wave forces than other numerical methods do. Therefore, the methodology presented herein can be used in the design of coastal and ocean structures.     

Statistics of Wave Crest Characteristics

The statistical distribution of wave crest characteristics such as crest length, crest height, joint crest height and length are analyzed based on numerical simulation of 3-D random waves. The effects of directional functions and wave crest defining methods on crest characteristics are also studied.The results show that wave crests are no longer uniform and continuous in directional wave field; the distribution of crest length is obviously influenced by the directional function; the statistics of crest characteristics obtained by the two different methods are almost the same.     

Numerical Simulation and Physical Simulation of Sea Wave Groups

- Based on field wave data, an empirical formula of wave envelope spectrum is given in this paper. Then the methods of both numerical and physical simulation of sea wave groups with the given spectrum and groupiness parameters are suggested.