共查询到20条相似文献，搜索用时 125 毫秒
1.
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
2.
任意曲线边界条件下缓变水深水域波浪传播的数值模拟 总被引：3，自引：0，他引：3
缓坡方程被广泛地应用于描述波浪的传播变形计算,目前一般采用矩形网格求解.将计算域剖分为任意四边形网格,以格林公式为基础,在变量沿单元边界线性变化的假定下,对双曲型的波能守恒方程、波数矢无旋性方程进行离散,同时通过等参单元变换推求节点偏导数值以离散椭圆型光程函数方程,从而建立了任意曲线边界条件下缓变水深水域波浪传播的数值模拟模型.将模型应用于平行直线型等深线地形,并将计算域剖分为不规则四边形网格,对不同入射角、底坡、波高等多种组合情况比较了数值解与解析解,结果表明两者一致.应用于复杂边界的实例,数值模拟结果与物模实验值基本吻合. 相似文献
3.
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
4.
椭圆型缓坡方程的一个有效的有限元解 总被引：7，自引：0，他引：7
将海绵层消波的方法用于有限元方法中,提出了缓坡方程的一种有效的有限元求解方法.在应用有限元法求解椭圆型缓坡方程时,通过在方程中加摩阻项,并在入射边界(波浪由此边界进入计算域)处使用不连续单元,将绕射势从总势中分离出来,在边界上利用海绵层进行消波处理,有效地消除了由于引用放射边界条件引起的误差和数值反射现象. 相似文献
5.
针对无限水深下波浪与二维水面物体相互作用问题,传统的波浪格林函数形式复杂、计算缓慢,为了提高计算效率和计算精度,将流域分为物体周围的内域及远离物体的外域,内域采用简单格林函数法,外域采用多极子展开方法,通过内外域边界匹配,耦合求解得到流域中任意一点的速度势,并可计算物体在波浪作用下的波浪激振力、附加质量、辐射阻尼及透射和反射系数。应用该方法计算了二维水面漂浮半圆和水面漂浮方箱的算例,数值计算结果表明,该方法可以方便、准确、快速地计算无限水深下波浪与任意漂浮物体的作用问题。 相似文献
6.
非线性波浪时域计算的三维耦合模型 总被引：3，自引：1，他引：2
将计算区域Ω划分为内域Ω1和外域Ω2(Ω2=Ω-Ω1),外域控制方程采用改进线性频散特性的二维Boussinesq方程,用预报一校正法数值求解;结构物附近的内域控制方程为三维Navier-Stokes方程,由VOF方法数值求解。通过在外域和内域相匹配的交界面上设置合适的速度和波面边界条件,建立了三维非线性波浪时域计算的耦合模型。模拟试验表明:(1)耦合模型数值波浪水池可以产生稳定的、重复性较好的波动过程;(2)用耦合模型数值波浪水池求解较大浅水区域上的非线性波浪数值计算问题可以取得较高的计算效率,同时又能得出结构物附近的复杂流场。 相似文献
7.
8.
在近岸缓坡浅水海岸,波浪破碎产生沿岸流是近岸海域流场的重要组成部分,它对污染物输移扩散规律的影响重大,在高阶近似抛物化缓坡方程求解大面积波浪场基础上,建立了波浪作用下污染物输移扩散数学模型.计算结果与不同坡度均匀斜坡地形上具有不同波高、周期的规则波及不规则波浪作用下污染物输移扩散实验结果进行了比较,分析了各种因素对波浪作用下沿岸流分布规律影响,所得结论认为地形坡度及入射波高对污染物输移扩散的影响较大,波浪作用将使缓坡海滩上污染物的输移扩散平行岸线方向. 相似文献
9.
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
10.
基于ArcGIS平台提取水深、坡度、粗糙度等地形特征,采用全覆盖多波来声纳测深数据,将南大西洋中脊研究区划分为4 267个统计单元,提取单元内地形特征的统计参数:均值、方差、最大值、最小值;经过统计筛选,最终选取水深均值、方差、最大值、最小值,坡度均值、方差、最大值、最小值共8个变量参与地形分类;利用K-均值方法进行非监督分类,将4 267个统计单元划分为5类地形,其中1 300个统计单元为裂谷,671个为裂谷壁,150个为内角高地斜坡,1 052个为高粗糙度的高地,1 093个为低粗糙度的次高地。将地形类型与地质调查结果进行初步关联,计算各类地形100网格见矿率系数,得到"内角高地斜坡"为热液硫化物发育的大概率地形类型,建议作为后继调查的重点勘探靶区。 相似文献
11.
A composite numerical model is presented for computing the wave field in a harbor. The mild slope equation is discretized by a finite element method in the domain concerned. Out of the computational domain, the water depth is assumed to be constant. The boundary element method is applied to the outer boundary for dealing with the infinite boundary condition. Because the model satisfies strictly the infinite boundary condition, more accurate results can be obtained. The model is firstly applied to compute the wave diffraction in a narrow rectangular bay and the wave diffraction from a porous cylinder. The numerical results are compared with the analytical solution, experimental data and other numerical results. Good agreements are obtained. Then the model is applied to computing the wave diffraction in a square harbor with varying water depth. The effects of the water depth in the harbor and the incoming wave direction on the wave height distribution are discussed. 相似文献
12.
A composite numerical model is presented for computing the wave field in a harbor. The mild slope equation is discretized by a finite element method in the domain concerned. Out of the computational domain, the water depth is assumed to be constant. The boundary element method is applied to the outer boundary for dealing with the infinite boundary condition. Because the model satisfies strictly the infinite boundary condition, more accurate results can be obtained. The model is firstly applied to compute the wave diffraction in a narrow rectangular bay and the wave diffraction from a porous cylinder. The numerical results are compared with the analytical solution, experimental data and other numerical results. Good agreements are obtained. Then the model is applied to computing the wave diffraction in a square harbor with varying water depth. The effects of the water depth in the harbor and the incoming wave direction on the wave height distribution are discussed. 相似文献
13.
N. Booij 《Coastal Engineering》1983,7(3):191-203
The mild-slope equation is a vertically integrated refraction-diffraction equation, used to predict wave propagation in a region with uneven bottom. As its name indicates, it is based on the assumption of a mild bottom slope. The purpose of this paper is to examine the accuracy of this equation as a function of the bottom slope. To this end a number of numerical experiments is carried out comparing solutions of the three-dimensional wave equation with solutions of the mild-slope equation.For waves propagating parallel to the depth contours it turns out that the mild-slope equation produces accurate results even if the bottom slope is of order 1. For waves propagating normal to the depth contours the mild-slope equation is less accurate. The equation can be used for a bottom inclination up to 1:3. 相似文献
14.
James R. Houston 《Applied Ocean Research》1981,3(4):163-170
A two-dimensional finite element numerical model is presented that calculates combined refraction and diffraction of short waves. The wave equation solved governs the propagation of periodic, small amplitude surface gravity waves over a variable depth seabed of mild slope. An efficient computational scheme is employed that allows the solution of practical problems that typically require large computational grids. Comparisons are presented between the finite element model calculations and an analytical solution, a two-dimensional numerical solution, a three-dimensional numerical solution, and measurements from a hydraulic model. 相似文献
15.
Nonlinear Dispersion Relation in Wave Transformation 总被引：13，自引：1，他引：13
1 .Ｉｎｔｒｏｄｕｃｔｉｏｎ1ＴｈｉｓｗｏｒｋｗａｓｆｉｎａｎｃｉａｌｌｙｓｕｐｐｏｒｔｅｄｂｙｔｈｅＮａｔｕｒａｌＳｃｉｅｎｃｅＦｏｕｎｄａｔｉｏｎｏｆＣｈｉｎａ (ＧｒａｎｔＮｏ .4 0 0 760 2 6ａｎｄ 4 0 0 760 2 8) Ｃｏｒｒｅｓｐｏｎｄｉｎｇａｕｔｈｏｒ.Ｅ ｍａｉｌ:ｒｊｌｉ@ｈｈｕ .ｅｄｕ .ｃｎ Ｉｔｉｓａｖｅｒｙｕｓｅｆｕｌａｎｄｅｆｆｅｃｔｉｖｅｗａｙｔｏａｄｊｕｓｔｔｈｅｗａｖｅｄｉｓｐｅｒｓｉｏｎｒｅｌａｔｉｏｎｆｏｒｔｈｅｓｔｕｄｙｏｆｔｈｅｎｏｎ ｌｉｎｅａｒｉｔｙｏｆｗａｖｅｐｒｏ… 相似文献
16.
利用有限元方法求解双曲型缓坡方程 总被引：4，自引：1，他引：4
本文提出了一种双曲型缓坡方程的有限元计算方法 ,在建立有限元积分方程时通过在造波线处加入脉动源项来实现内部造波 ,并在开边界处利用阻尼层吸波 ,减少了在边界处由于数值处理引起的误差。数值计算结果与实测值吻合良好。本方法可用于大区域波浪场的计算中 相似文献
17.
A non-linear coupled-mode system of horizontal equations is presented, modelling the evolution of nonlinear water waves in finite depth over a general bottom topography. The vertical structure of the wave field is represented by means of a local-mode series expansion of the wave potential. This series contains the usual propagating and evanescent modes, plus two additional terms, the free-surface mode and the sloping-bottom mode, enabling to consistently treat the non-vertical end-conditions at the free-surface and the bottom boundaries. The present coupled-mode system fully accounts for the effects of non-linearity and dispersion, and the local-mode series exhibits fast convergence. Thus, a small number of modes (up to 5–6) are usually enough for precise numerical solution. In the present work, the coupled-mode system is applied to the numerical investigation of families of steady travelling wave solutions in constant depth, corresponding to a wide range of water depths, ranging from intermediate depth to shallow-water wave conditions, and its results are compared vs. Stokes and cnoidal wave theories, as well as with fully nonlinear Fourier methods. Furthermore, numerical results are presented for waves propagating over variable bathymetry regions and compared with nonlinear methods based on boundary integral formulation and experimental data, showing good agreement. 相似文献
18.
《Coastal Engineering》1999,37(2):175-192
Nonlinear wave diffraction is studied using the nonlinear time-dependent mild slope equation. The equations are solved using a combined Newton–Raphson and Crank–Nicolson finite difference scheme. The model results are verified for propagation of highly nonlinear waves over uniform depth and wave diffraction due to semi-finite breakwater and breakwater gap with different widths. Comparison between the numerical and experimental results indicates that the model is capable of simulating nonlinear wave diffraction. The model is applied to study the effect of the wave nonlinearity on the diffraction coefficient for a semi-infinite breakwater and a breakwater gap. 相似文献
19.
Lin Mingchung Hsiao Sungshan Hsu Yungcheng
Professor Dept. of Naval Architecture Ocean Engineering National Taiwan University Taiwan. Doctor Course Student Dept. of Naval Architecture Ocean Engineering National Taiwan University Taiwan 《中国海洋工程》1994,(3)
-Wave refraction-diffraction due to a large ocean structure and topography in the presence of a 'current are studied numerically. The mathematical model is the mild-slope equation developed by Kirby (1984). This equation is solved using a finite and boundary element method. The physical domain is devid-ed into two regions: a slowly varying topography region and a constant water depth region. For waves propagating in the constant water depth region, without current interfering, the mild- slope equation is then reduced to the Helmholtz equation which is solved by boundary element method. In varying topography region, this equation will be solved by finite element method. Conservation of mass and energy flux of the fluid between these two regions is required for composition of these two numerical methods. The numerical scheme proposed here is capable of dealing with water wave problems of different water depths with the main characters of these two methods. 相似文献
20.
The structure, evolution, and breaking of a tidal internal wave on a steep shelf are discussed on the basis of the data of temperature measurements. The bottom slope at the measurement site is close to the critical slope for a tidal wave. The tidal wave and other waves are inclined coastward. The tidal-wave amplitude increases monotonically with increasing horizon depth. The tidal wave is nonlinear in amplitude and turns over on the outer shelf. On the inner shelf, the internal wave is close in shape to rectangular and generates harmonics of its own. The harmonics make the tidal wave steeper and form solitary rises similar to bilateral bores. All these features ensure a more rapid sink for the internal-tide energy. 相似文献