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近岸波浪增水与近岸流的计算方法研究 总被引：2，自引：1，他引：2
本文针对实际波浪及地形的复杂性，提出了一套用于计算缓坡不规则地形上波浪增水与近岸流的数学模型。该模型采用经典的力学平衡机制，以二维不规则波浪为源动力，并着考虑了近岸波浪与波浪增水之间的相互作用，其物理背景符合工程应用的要求。 相似文献
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在时域缓坡方程中,引入非线性修正项、高阶地形影响项以及能量耗散项,推导得出扩展型双曲缓坡方程。基于该方程,利用ADI格式建立波浪传播数学模型,并应用于椭圆形浅滩、Bragg反射正弦沙涟地形以及斜坡地形的波浪传播计算,计算结果与试验数据均吻合良好,表明该模型能够对近岸波浪的折射、绕射、反射、浅水变形、弱非线性、陡变地形影响以及破碎进行较好地模拟。 相似文献
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基于改进缓坡方程的波浪传播数值模拟 总被引：1，自引：1，他引：0
用变分原理导出考虑底坡一阶导数平方项和二阶曲率项影响的缓坡方程,对传统缓坡方程作了改进,提高波浪在海底地形变化剧烈、水深较浅时数值模拟精度。数值计算与已有实验室试验资料比较表明,该模型可以较好地模拟有剧烈变化的海底地形的波浪传播,比传统缓坡方程模型计算结果在精度上有明显提高。 相似文献
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浪致近岸水位变化及流场的数值计算 总被引：6，自引：1，他引：6
本文探讨了单频波浪入射到具有复杂地形（缓变坡度）的近岸水域所导致的水位变化和近岸流场的数值计算问题。用了联合折射－绕射波浪场模型方程确定波要素，对一个模型海区和一个实际海区进行了实际计算。讨论了考虑和不考虑绕射效应的波浪场对水位变化及近岸流场的影响。数值计算结果表明，计算的水位变化和近岸流场都是（定性）合理的，岸坡水位最大升高达深水入射波高的１１．２％～１５．３％（以上）；考虑和不考虑绕射效应的波浪场对计算的水位变化和近岸流场都有影响，特别是对流速量值影响很大。 相似文献
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目前的拍岸浪统计计算模型主要针对缓坡地形,对于陡坡-礁盘地形拍岸浪计算模型的研究还非常少。本文中整理了国际上多种拍岸浪统计计算模型,利用波浪水槽实验数据检验了这些模型在陡坡-礁盘地形上的适用性,推荐Komar模型用于陡坡拍岸浪计算。基于波浪水槽实验对比分析了缓坡地形和陡坡-礁盘地形上的拍岸浪演变特征,初步提出了礁盘地形上一种新型拍岸浪统计计算模型,它和Komar模型组合,对陡坡-礁盘地形的拍岸浪具有较强的模拟能力。计算得到陡坡段和礁盘段破碎波高的平均相对误差分别为4.45%和5.04%。本文研究成果可以为岛礁地形上拍岸浪的预报及相关数值模拟研究等提供数据和参考。 相似文献
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波浪在斜坡地形上破碎,破波后稳定波高多采用物理模型试验方法进行研究,利用近岸波浪传播变形的抛物型缓坡方程和波能流平衡方程,导出了适用于斜坡上波浪破碎的数值模拟方法。首先根据波能流平衡方程和缓坡方程基本型式分析波浪在破波带内的波能变化和衰减率,推导了波浪传播模型中波能衰减因子和破波能量流衰减因子之间的关系;其次,利用陡坡地形上的高阶抛物型缓坡方程建立了波浪传播和波浪破碎数学模型;最后,根据物理模型试验实测数据对数值模拟的效果进行验证。数值计算与试验资料比较表明,该模型可以较好地模拟斜坡地形的波浪传播波高变化。 相似文献
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四叉树网格下的椭圆型缓坡方程数值模型研究 总被引：1，自引：1，他引：0
波浪是近岸海域关键的水动力因素之一。考虑到近岸地形复杂、波浪演化显著的特点,建立了四叉树网格体系下的椭圆型缓坡方程数值模型,采用有限体积法对模型进行数值离散,应用GPBiCG(m, n)算法求解离散后的控制方程。模型中根据波浪波长布局计算网格,生成多层次四叉树网格,对复杂计算域有较好的适应性,并且在离散和方程求解中无需引入形函数、不产生复杂的交叉项,节约了存储空间和计算时间。将模型成功应用于物理模型实验及Acapulco海湾的波浪场数值模拟,结果表明该模型能够准确、高效地模拟近岸波浪场,可为近岸波浪场的模拟提供一定的理论和技术支持。 相似文献
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波浪的非线性弥散关系在应用于求解波浪的变形问题时很不方便，需要与含非线性效应的缓坡方程一起进行迭代运算，往往导致数值计算的计算量太大，计算过于复杂。采用显式形式表达非线性弥散关系，可以克服上述缺点，大为简化波浪变形数值计算的计算量。本文通过将现有的非线性弥散关系进行分析比较，给出了一个更为一般的非线性弥散关系及其显式表达式，经比较可知，该显式弥散关系与相对应非线性弥散关系吻合的很好。本文最后用该显式结合含弱非线性效应的缓坡方程，对复式浅滩地形上的波浪折射绕射进行了计算。结果表明，考虑弱非线性可以得出与实验数据更为相符的结果，而采用显式弥散关系可以有效提高计算效率,在波浪的非线性计算中不失为一种切实有效的方法。 相似文献
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Fengyan Shi Robert A. Dalrymple James T. Kirby Qin Chen Andrew Kennedy 《Coastal Engineering》2001,42(4):258
Based on the fully nonlinear Boussinesq equations in Cartesian coordinates, the equations in generalized coordinates are derived to adapt computations to irregularly shaped shorelines, such as harbors, bays and tidal inlets, and to make computations more efficient in large near-shore regions. Contravariant components of velocity vectors are employed in the derivation instead of the normal components in curvilinear coordinates or original components in Cartesian coordinates, which greatly simplifies the equations in generalized curvilinear coordinates. A high-order finite difference scheme with staggered grids in the image domain is adopted in the numerical model. The model is applied to five examples involving curvilinear coordinate systems. The results of these cases are in good agreement with analytical results, experimental data, and the results from the uniform grid model, which shows that the model has good accuracy and efficiency in dealing with the computations of nonlinear surface gravity waves in domains with complicated geometries. 相似文献
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A BFG model for calculation of tidal current and diffusion of pollutants in nearshore areas 总被引：4，自引：0，他引：4
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Researches on breaking-induced currents by waves are summarized firstly in this paper. Then, a combined numerical model in orthogonal curvilinear coordinates is presented to simulate wave-induced current in areas with curved boundary or irregular coastline. The proposed wave-induced current model includes a nearshore current module established through orthogonal curvilinear transformation form of shallow water equations and a wave module based on the curvilinear parabolic approximation wave equation. The wave module actually serves as the driving force to provide the current module with required radiation stresses. The Crank-Nicolson finite difference scheme and the alternating directions implicit method are used to solve the wave and current module, respectively. The established surf zone currents model is validated by two numerical experiments about longshore currents and rip currents in basins with rip channel and breakwater. The numerical results are compared with the measured data and published numerical results. 相似文献
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For the simulation of the nonlinear wave propagation in coastal areas with complex boundaries,a numerical model is developed in curvilinear coordinates. In the model,the Boussinesq-type equations including the dissipation terms are employed as the governing equations. In the present model,the dependent variables of the transformed equations are the free surface elevation and the utility velocity variables,instead of the usual primitive velocity variables. The introduction of utility velocity variables which... 相似文献
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边界拟合坐标下流场计算模式 总被引：1，自引：0，他引：1
流场数值模拟中，采用曲线坐标法准确模拟计算水域自然边界情形是当今研究的热点之一。本文借助于自然界中某些物理现象中其函数符合椭圆型且必然正交这一特性，建立了曲线坐标系，弥补在笛卡尔坐标系下二维流场模拟的边界贴合不足。应用本模式对我国某一河口水域的潮位和流场进行计算，结果表明；该模式具有物理意义清晰、稳定性良好、精度高等特点，模式对实际工程中流场模拟具一定的应用价值。 相似文献
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A WDM method on a generalized curvilinear grid for calculation of storm surge flooding 总被引：1，自引：0，他引：1
In this paper, the wet-dry grid point method (WDM) with generalized curvilinear computation grids is introduced with the aim of presenting a kind of effective numerical model for real-time forecasting of storm surge flooding. To realize this general WDM method, generalized 2-D shallow sea dynamic equations in curvilinear co-ordinates are derived, and the contravariant components of the velocity vector are employed for easily realizing boundary conditions and making the wet-dry point judgement criterion more reasonable. As the generalized equations are not limited to a specific co-ordinate transformation, a self-adaptive grid generation method, which optimizes simultaneously grid smoothness, orthogonality and variation in cell volumes, is then proposed to meet the needs of WDM with varying spacing grids. The paper also provides a numerically stable difference scheme and this scheme is proved accurate by the verification calculation of observed storm surge. 相似文献
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A quasi-linear model for determining the aerodynamic drag coefficient of the sea surface and the growth rate of surface waves under a hurricane wind is proposed. The model explains the reduction (stabilization) in the drag coefficient during hurricane winds. This model is based on the solution of the Reynolds equations in curvilinear coordinates with the use of the approximation of the eddy viscosity, which takes into account the presence of the viscous sublayer. The profile of the mean wind velocity is found with consideration for nonlinear wave stresses (wave momentum flux), whereas wave disturbances induced in air by waves on the water surface are determined in the context of linear equations. The model is verified by comparing the calculation results with experimental data for a wide range of wind velocities. The growth rate and drag coefficient for hurricane winds are calculated both with and without consideration for the shortwave portion of the windwave spectrum. On the basis of calculations with the quasi-linear model, a simple parametrization is proposed for the drag coefficient and the growth rate of surface waves during hurricane winds. This model is convenient for use in models of forecasting winds and waves. 相似文献
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In hydrodynamic models of marine and estuarine currents the use of boundary-fitted curvilinear grids not only makes the model grids fit to the coastline and bathymetry well, but also makes the kinetic boundary conditions simple and more accurate. Because of these advantages, a three-dimensional tidal model with boundary-fitted curvilinear grids has been developed to simulate both tide and current in estuarine and shelf water. The basic idea is to use a set of coupled σ-stretched and elliptic transformations to map the physical space into a corresponding transformed space such that all boundaries are coincident with co-ordinate lines and the transformed grids are rectangular. The hydrodynamic equations in the transformed space are solved in a rectangular mesh of the transformed grid system. The application of the model in the simulation of the M2,S2 , K1and O1tidal waves in the Bohai Sea, China, shows that the numerical results are in good agreement with the observations. The method of boundary-fitted curvilinear grids is effective for improving simulation accuracy of current in the estuarine and shallow seas, especially at the coastal regions where the current was usually impractical by a uniform Cartesian grid system with the shoreline and bathymetry represented by numerous stair-steps. 相似文献
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为阐明伶仃洋河口水域纳潮现状和特性,分别采用经验公式和建立贴体曲线坐标系下的珠江河口二维数学模型的方法,对河口伶仃洋水域的纳潮特性进行了分析和探讨.数学模型的离散和求解采用纯隐格式的混合有限分析法,根据实测资料对其进行了验证.比较显示,采用实测资料和经验公式计算到的伶仃洋水域纳潮量与数学模型的计算结果相差在5%以内,从而证实了数学模型的可靠性.结果表明,伶仃洋海域的主要纳潮口门为伶仃洋口门,约占总纳潮量的87.7%,通过香港暗士顿水道进出的潮量仅占12.3%左右,显示伶仃洋口门为该海域的主要径潮通道,对该河口的防洪和生态具有重要的作用 相似文献
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通过比较常用地形σ坐标的流体静力中尺度大气控制方程的一般导出与利用张量分析法的导出,分析了前者只限用于很小地形坡度的原因。根据后者对前者作了修正,给出适用于较陡地形坡度的流体静力控制方程。并借助修正了的Ｐｉｅｌｋｅ数值模式模拟气流过山的流场特征,说明修正的作用与意义。 相似文献