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南海珠江口盆地陆架斜坡及大陆坡海底沙波动态分析 总被引：19，自引：2，他引：19
探索陆架与陆坡海底动力地貌演变规律,不仅是学科理论发展上的重要研究课题,同时也是国土开发和研究海洋工程环境的需要。文中基于作者提出的床面稳定中的“准共振界面波”理论模式,针对南海北部“卫滩幅”地区海床微地貌在水动力条件作用下的现况进行了初步分析,得出水深80～250m海底小尺度沙波的形成机理与室内水槽和天然海滩上的沙纹沙丘的形成同属一个规律,这一推论已得到该地区现场资料的初步验证。文中最后还就现有同行专家的研究成果估算了上述地区沙波的移动趋势。 相似文献
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为研究内孤立波与沙波的相互作用,本文对基于OpenFOAM的SedWaveFoam求解器进行改进,建立了内孤立波-泥沙运动欧拉两相流模型。在利用试验资料对模型进行验证的基础上,在南海北部典型代表性条件下,模拟分析了500 m水深位置沙波床面上内孤立波作用下的水动力变化和泥沙运动。结果表明,内孤立波逐渐离开沙波时,海底沙波背流面处出现与内孤立波背景流速反向的流速,在内孤立波导致的流场作用下,沙波床面上的泥沙悬起并运动到床面以上的水体中。振幅100 m的内孤立波可以导致床面以上14 m高的位置处出现约0.07 kg/m3的悬沙浓度。 相似文献
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基于量纲分析理论进行水槽试验,研究了潮流以及单向流作用下海底沙波的形成和发展过程。通过分析
海床地形数据,对海底沙波的特征尺度和发展过程进行定量描述,得出了潮流流速、周期、水深以及叠加单向流等因素对沙波特征尺度的影响。结果表明,潮流作用产生的海底地貌由大尺度的沙波和小尺度的沙纹共同组成,大尺度沙波在地貌形态塑造中占主导地位。从平坦海床开始,沙波波高和波长随水流作用逐渐增大,增长速度越来越慢,最终达到动态平衡。沙波特征波高和特征波长随流速和水深增大而增大,同时随往复流周期的增大而增大,并不断趋近于单向水流的情况。进一步对小尺度的沙纹地貌进行分析,得出了沙纹特征尺度随水流条件的变化规律。 相似文献
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依据深海表面波的非线性薛定谔方程,推导深海表面波的增益谱,研究在调制不稳定条件下的非线性薛定谔方程的一阶解与增益之间的关系,又结合呼吸孤子产生畸形波的现象,得到畸形波的最大振幅为初始波振幅与增益最大值的叠加。这个结果对研究畸形波的产生具有一定的参考价值。 相似文献
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对2006年8月所获台湾浅滩的底质、水深、多层位流速、流向以及CTD观测数据进行了分析,探讨了台湾浅滩大型沙波区水流的时空分布特征、沉积物输运过程及影响因素,结果表明,台湾浅滩动力作用较强,底质为粗砂,其上发育的沙波波长为325~822 m,波高为14.4~20.3 m,较接近由前人总结的沙波波高、波长的关系式计算出的波高和波长。沙波波峰、波谷、迎水面和背水面流速以12.5 h为周期沿顺时针方向旋转;底部最大流速出现在半日潮周期的同一时段,对应的方向均为偏南方向,且沙波迎水面的流速大于背水面的。在两个半日潮过程中研究区域的沉积物输入量大于输出量,处于淤积状态。在潮流作用下沉积物输运量较少,沙波脊线移动较小,而台湾浅滩有较大规模的沙波运动,故认为改造沙波的主要作用力应该是风暴流。在观测的断面中涨潮推移质输运量大于落潮的,且第一个半日潮涨落潮的输运能力均较第二个半日潮的大,这可能与潮流的流速-时间不对称特征及潮能变化形式有关。 相似文献
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基于秘鲁钱凯港的防波堤三维整体模型试验结果,研究了涌浪绕射、透射联合作用对港内波况的影响。分析了不同波向、不同谱峰周期的入射波条件下港内不同功能区的波况分布规律,并对比分析了具有不同周期的入射波对港内不同区域波高的影响,兼顾分析了波向的影响。结果表明,在涌浪作用下,受透射、绕射影响,不同入射波条件下港内比波高分布规律相关性较好,距离口门越近、入射波波长越长,港内比波高越大;入射波周期对港内波况影响的差异和对波向的敏感性因港内不同区域而不同;防波堤阻挡效果好的波向,其入射波对港内的影响较小;对于受防波堤掩护性较好的内侧泊位,应重点关注泊位处的低频波浪对系泊的影响。 相似文献
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Zhang Yonggang Li Yucheng Associate Professor Dept. of Mechanic Engineering Shanghai Jiao Tong University Shanghai Professor Dept. of Civil Engineering Dalian University of Technology Dalian 《中国海洋工程》1998,(1)
A nonlinear numerical model has been set up by use of Boussinesq Equation with finite differ-ence method,and has been applied to the simulation of the abnormal change of wave height induced by ex-cavated waterway.Numerical results demonstrate that the abnormal change of wave height is due to theadding of the reflected wave height induced by excavated waterway to the incident wave height.Becausethe angle between the incident wave and the axis of the waterway is smaller than the critical angle,the re-flected wave produced by the waterway may propagate to the breakwater and may be added with the inci-dent wave,then the abnormal change of wave height before the breakwater may be caused.So the wave re-flection caused by the change of water depth cannot be neglected. 相似文献
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Based on the full water-wave equation, a second-order analytic solution for nonlinear interaction of short edge waves on a constant plane sloping bottom is presented in this paper. For special case of slope angle b=p/2, this solution can be reduced to the same order solution of deep water gravity surface waves traveling along parallel coastline. Interactions between two edge waves including progressive, standing and partially reflected standing waves were also discussed. The unified analytic expressions with transfer functions for kinematic-dynamic elements of edge waves were also discussed. The random model of the unified wave motion processes for linear and nonlinear irregular edge waves is formulated, and the corresponding theoretical autocorrelation and spectral density functions of the first and second orders are derived. The boundary conditions for the determining determination of the parameters of short edge wave are suggested, that may be seen as one special simple edge wave excitation mechanism and an extension to the sea wave refraction theory. Finally some computation results are demonstrated. 相似文献
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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
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1 IntroductionRecently breakwaters with perforated front wallshave been widely used. The use of perforated break-waters mainly has two advantages. Firstly, wave forcesacting on the whole structure can be divided into twoparts on two different walls with a phase difference.To select the distance between the two plates suitably,the total wave force on the whole structure can bemaintained at a low level. Secondly, waves will dissi-pate when they transmit over a porous medium. Thus,the reflection… 相似文献
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Based on the full water-wave equation,a second-order analytic solution for nonlinear interaction of short edge waves on a plane sloping bottom is presented in this paper.For special case of slope angle β=π/2,this solution can reduced to the same order solution of deep water gravity surface waves traveling along parallel coastline.Interactions between two edge waves including progressive,standing and partially reflected standing waves are also discussed.The unified analytic expressions with transfer functions for kinematic-dynamic elements of edge waves are also given.The random model of the unified wave motion processes for linear and nonlinear irregular edge waves is formulated,and the corresponding theoretical autocorrelation and spectral density functions of the first and the second orders are derived.The boundary conditions for the determination of the parameters of short edge wave are suggested,that may be seen as one special simple edge wave excitation mechanism and an extension to the sea wave refraction theory.Finally some computation results are demonstrated. 相似文献
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Laboratory Study on the Interaction Between Regular Obliquely Incident Waves and Vertical Walls 总被引：1，自引：3，他引：1
Li Yucheng 《中国海洋工程》2001,(2):195-203
The characteristics of wave forces are studied based on physical model tests with regular waves. The ratio of obliquely incident wave forces to normally incident wave forces on unit length of a vertical wall is related with various factors. A linear reduction of the mean force of obliquely incident waves is confirmed with an increase in the relative caisson length. Also the characteristics of reflection coefficient of diagonal waves are discussed. 相似文献
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斜向不规则波对直墙作用的实验研究 总被引：5，自引：1，他引：5
通过长峰不规则波和方向波谱对直墙作用的实验研究 ,分别给出了每延米斜向不规则波波浪力与正向力之比 ,方向波谱波浪力与斜向长峰不规则波波浪力之间的关系 ,通过与规则波实验结果的比较给出了斜向规则波与不规则波波浪力之间的相对关系 ;并对斜向不规则波的反射系数与正向波时的变化作出了分析 相似文献
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完全非线性孤立波的直墙反射 总被引：2，自引：2，他引：0
报道了应用边界积分方法模拟完全非线性孤立波的传播与直墙反射,给出了波形演变过程。结果表明,本模型对计算孤立波的传播与直墙反射是有效的。三阶Boussinesq方程的孤立波解比低阶方程的孤立波解更接近完全非线性的数值解.当来波波高增大时,孤立波直墙反射的相位滞后变小。若考虑大波高孤立波的直墙反射或波——波相互作用,一阶理论预报的相位滞后往往低估实际情况。 相似文献
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Yingguang Wang 《海洋学报(英文版)》2021,40(4):127-135
The power performances of a point absorber wave energy converter(WEC) operating in a nonlinear multidirectional random sea are rigorously investigated. The absorbed power of the WEC Power-Take-Off system has been predicted by incorporating a second order random wave model into a nonlinear dynamic filter. This is a new approach, and, as the second order random wave model can be utilized to accurately simulate the nonlinear waves in an irregular sea, avoids the inaccuracies resulting from using a first order linear wave model in the simulation process. The predicted results have been systematically analyzed and compared, and the advantages of using this new approach have been convincingly substantiated. 相似文献
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采用二阶时域理论对非线性波浪在任意三维物体周围的绕射问题进行了研究，对自由表面边界条件进行Taylor级数展开，应用摄动展开可以建立相应的边值问题，而且此边值问题的计算域不随时间变化，运用基于B－样条的边界元方法求解每一时刻的波浪场，二阶自由表面边界条件在时间上进行数值积分，在自由表面加了一个人工阻尼层以避免波浪的反射，速度势分解为已知的入射势和未知的散射势，初始条件采用二阶Stokes波浪场，通过加入物体表面边界条件，得到散射势在时间和空间上的发展，本文对圆柱所受规则波的二阶波浪力和波浪爬高进行了计算，数值结果表明此理论计算准确，效率高，数值稳定。 相似文献