巨型浮体闸门的非线性振荡

在模型试验时，发现巨型浮体闸门在非线性上有大幅度的谐和振荡，根据浮体闸六构造特征，建立了单自由度非线性振荡模型。由于闸门的自振周期是水位与垂直开度的函数，非线性约束对自振周期的影响也将是水位与一度的函数。还分析了不同开度情况下非线性约束对自振周期振幅的影响。     

空泡噪声的数值研究

空泡噪声是一个非线性动边界的声辐问题，作者针对这个特点，提出了一种新的数值方法-混合边界元法，本文应用混合边界元法对无界流场、自由面或固壁面附近空泡溃灭过程辐射的噪声进行计算，得到了空泡在不同情况下溃灭辐射声音的特征，结果显示混合边界元方法在这类动边界声辐射问题上，能体现出声音传播的延迟效应，体现出液体压缩性对声压峰值的影响，作者认为混合边界法在处理这类动边界声辐射问题上有着很好的应用前景。     

巨型浮体闸门的非线性振荡

在模型试验时，发现巨型浮体闸门在非线性约束下有大幅度的谐和振荡。根据浮体闸门的构造特征，建立了单自由度非线性振荡模型。由于闸门的自振周期是水位与垂直开度的函数，非线性约束对自振周期的影响也将是水位与开度的函数。还分析了不同开度情况下非线性约束对自振周期和振幅的影响。     

柔性连接多浮体在不规则波中运动的预报方法

本文介绍了一种频、时域杂交法，用于预报柔性连接多浮体在波浪中的运动。其中采用三维频域法适时求解浮体的水动力系数，在时域内求解浮体的运动方程，可同时求解非线性锚链力、连接器受力和护舷受力。利用本方法预报了柔性连接的“口”字形六浮体系统在波浪中的运动，结果与试验结果具有较好的吻合程度。     

浮体结构沉浮过程周围水流特性研究

浮体结构作为一种环境友好型装置已广泛应用于平原防洪水利工程，但在浮体沉浮过程中，周围水流变化会影响浮体结构的安全运行。采用物理模型试验，对浮体结构长度以及吃水深度不同时浮体周围的水力特性及回流区进行了测量分析。结果表明：由于浮体的阻挡，靠近浮体背水面位置的水流流速减小；吃水深度增大导致过水断面减小，最大流速增大且位置下移，回流区范围增加；浮体结构长度变化对流速分布影响较小，但随着长度增加，回流区长度减小；浮体长度的增加以及吃水深度的减小会提高浮体结构的稳定性。     

地基辐射阻尼和库水对拱坝非线性地震响应的影响

针对拱坝坝体—地基—水库系统的动力计算分析，采用考虑无限地基辐射阻尼、坝体横缝非线性和自由场输入的模型程序，以溪洛渡拱坝为工程实例，对不同库水位下，考虑或不考虑地基辐射阻尼的工况进行了系列的计算对比研究。研究结果显示，低水位是横缝开度控制工况，高水位是坝体应力控制工况；对所有水位，地基辐射阻尼都带来坝体地震响应的全面降低，但不影响反应的总体规律。     

浮体闸技术的发展与推广应用

1浮体闸发展概况浮体闸是利用水力学原理和新结构、新材料、新工艺而组合设计的水力自动闸门．1968年9月河南省临颖县水利局建成第一座黄龙渠浮体闸（8m×2m）．随后，于1970年建成大廓浮体闸（26．5m×4．5m），1971年作为技术革新成果在秋季的广州交易会上展出，并印发了简要的技术说明，这标志着第一代浮体闸的诞生（参见图1）．因此，浮体闸在全国各地兴建，先后建成23座不同规模的浮体闸．接着于1973年1月水利电力出版社出版了《浮体闸》一书，使浮体闸在全国各地得到更大的推广应用．据不完全的统计，全国已建浮体闸约50座．1972年初…     

双浮体自由垂向振荡响应特性

双圆柱体系统在波能装置和防波构件中得到应用，该系统是一个多自由度受迫阻尼振荡系统，阻力和激励力都来自于波浪力。本文采用线性波理论和特征函数展开皮配法，在平面入射波条件下，求解了双圆柱体垂荡运动辐射速度势和圆柱体固定不动时的绕射速度势，推导了附加质量、阻尼系数、波浪激励力表达式，列出了浮体垂荡运动微分方程。最后讨论了下浮体尺度及位置对系统响应特性的影响。数值计算表明无论下浮体尺度及位置如何变化，它只影响到浮体垂荡响应在低频端的值，下浮体的振幅值总是小于入射波的振幅值，而且它在一个较窄的频率范围内从较大的值很快变化接近于零。下浮体半径与上浮体半径之比的变化不仅影响到两个浮体的响应幅值，而且也影响到曲线的变化趋势；两浮体距离的变化对曲线的变化趋势影响不大，但对曲线的幅值有影响；下浮体厚度的变化只少许改变了响应曲线的幅值。     

静动水冰厚生长消融全过程的辐射冰冻度-日法预测研究

冰厚计算的传统方法冰冻度-日法具有两个缺点：（1）无法实现对冰盖消融过程的模拟;（2）公式中含有经验参数,需经实测数据校核后,计算结果才较为准确。针对以上两个问题。本文在深入研究不同水流条件下冰盖生长、消融机理的基础上,提出了静水、动水冰厚预测的辐射冰冻度-日法。采用统一的公式描述冰厚生长、消融的全过程,并通过对胜利水库和松花江冰厚生消过程的计算验证了算法的正确性。计算公式中没有经验参数,物理意义明确,适用范围广;静、动水冰厚辐射冰冻度-日法揭示出：（1）冰厚的生消演变主要是气温、辐射和水温综合作用的结果;（2）静水冰厚和动水冰厚生消机理的差别在于水温对静水冰厚的影响极小,可以忽略,而对于动水冰厚则极为重要;（3）辐射是冰厚消融的根本性原因。     

室内动力模型试验中辐射阻尼效应的模拟

在评价大型结构的地震响应时，基础的辐射阻尼效应必须以适当的方法计入。本文研究在室内振动台动力模型试验中应用阻尼边界对辐射阻尼效应的模拟方法。通过利用黏滞液体的剪切黏性形成人工边界切向边界阻尼，实际阻尼系数易于调整控制。对于法向边界阻尼的影响，通过对试验模型的数值模拟对比计算进行了论证。结果表明，在仅施加切向边界阻尼的条件下，就能够消耗大部分由边界外传的能量，是可行的模型制作方案，大大降低了试验模型制作难度。     

CALCULATION OF NONLINEAR FREE－SURFACE FLOWS RESULTING FROM LARGE￣AMPLITUDE FORCED OSCILLATION OF A TWO－DIMENSIONAL BODY

ＣＡＬＣＵＬＡＴＩＯＮ　ＯＦ　ＮＯＮＬＩＮＥＡＲ　ＦＲＥＥ－ＳＵＲＦＡＣＥ　ＦＬＯＷＳ　ＲＥＳＵＬＴＩＮＧ　ＦＲＯＭ　ＬＡＲＧＥ￣ＡＭＰＬＩＴＵＤＥ　ＦＯＲＣＥＤ　ＯＳＣＩＬＬＡＴＩＯＮ　ＯＦ　Ａ　ＴＷＯ－ＤＩＭＥＮＳＩＯＮＡＬ　ＢＯＤＹＣＡＬＣＵＬ...     

Finite element analysis of second order wave radiation by a group of cylinders in the time domain

A finite element based numerical method is employed to analyze the wave radiation by multiple or a group of cylinders in the time domain. The nonlinear free surface and body surface boundary conditions are satisfied based on the perturbation method up to the second order. The first- and second-order velocity potential problems at each time step are solved through a Finite Element Method (FEM). The matrix equation of the FEM is solved through iteration and the initial solution is obtained from the result at the previous time step. The three-dimensional (3-D) mesh required is generated based on a two-dimensional (2-D) hybrid mesh on a horizontal plane and its extension in the vertical direction. The hybrid mesh is generated by combining an unstructured grid away from cylinders and two structured grids near the cylinder and the artificial boundary. The fluid velocity on the free surface and the cylinder surface are calculated by using a differential method. Results for various configurations including the cases of two cylinders and four cylinders and a group of eighteen cylinders are obtained to show the joint influences of cylinders on the first- and second-order waves and forces, including the effects of spacing ratios and wave frequency on the second order waves and the mean force, in particular.     

VOF方法模拟波浪槽中二维非线性波

造波板运动生成非线性波问题是研究物体与波浪非线性相互作用的典型例子。本文研究了用ＶＯＦ方法模拟波浪水槽生成非线性波（孤立波和椭圆余弦波）的问题，为实现造波板在计算中可以做穿越网格的大幅值运动，本文采用在压力迭代中调整造波板邻近单元中压力来满足造波板上流体运动条件。对开路边界条件和自由表面与物面交点处边界条件也提出了处理方法，计算结果与实验结果和解析结果进行了对比。     

Time domain simulations of radiation and diffraction by a Rankine panel method

The radiation and the diffraction of a ship with a forward speed are studied by using a time domain Rankine panel method. The free surface conditions are linearized onto an undisturbed free surface based on the double body flow. The linearized body boundary condition is applied on the mean wetted hull surface. The fluid domain boundary is discretized by a collection of quadric panels. The unknown quantities, including the free surface elevation, the normal flux over the free surface and the potential on the fluid domain boundary, are determined at each time step. The numerical results are compared with experimental data and other numerical solutions, showing satisfactory agreements.     

Iterative Rankine HOBEM analysis of hull-form effects in forward-speed diffraction problem

A time-domain numerical algorithm based on the higher-order boundary element method and the iterative time-marching scheme is proposed for seakeeping analysis. The ship waves generated by a hull advancing at a constant forward speed in incident waves and the resultant diffraction forces acting on the hull are computed to investigate the hull-form effects on the hydrodynamic forces. A rectangular computational domain travelling at ship's speed is considered. An artificial damping beach for satisfying the radiation condition is installed at the outer portion of the free surface except the downstream side. An iterative time-marching scheme is employed for updating both kinematic and dynamic free-surface boundary conditions for numerical accuracy and stability. The boundary integral equation is solved by distributing higher-order boundary elements over the wetted body surface and the free surface. The hull-form effects on the naval hydrodynamics are investigated by comparing three different Wigley models. Finally, the corresponding unsteady wave patterns and the wave profiles around the hulls are illustrated and discussed.     

An iterative Rankine BEM for wave-making analysis of submerged and surface- piercing bodies in finite water depth

A 3-D iterative Rankine Boundary Element Method （BEM） for seakeeping problem in time domain is developed in the framework of linear potential theory. Waves generated by both submerged and surface-piercing bodies moving at a constant forward speed in otherwise calm water, and the resultant steady wave pattern, wave profile and resistance are computed to validate this newly-developed code. A rectangular computational domain moving with the same forward speed as the body is introduced, in which an artificial damping beach is installed at an outer portion of the free surface except the downstream side for satisfying the radiation condition. The velocity potential on the ship hull and the normal velocity on the free surface are obtained directly by solving the boundary integral equation, with the Rankine source used as the kernel function. An iterative time-marching scheme is employed for updating both kinematic and dynamic free surface boundary conditions to stabilize the calculation. Extensive results including the wave patterns, wave profiles and wave resistances for a submerged spheroid and a Wigley hull with forward speed are presented to validate the efficiency of the proposed 3-D time-domain higher-order approach. Finally, the sensitivity of ship-generated waves to the water depth is investigated. Computed results show satisfactory agreement with the corresponding experimental data and other numerical solutions.     

FULLY NONLINEAR CALCULATION OF 2－D WATER WAVE GENERATED BY ROCKER FLAP WAVEMAKER

ＦＵＬＬＹＮＯＮＬＩＮＥＡＲＣＡＬＣＵＬＡＴＩＯＮＯＦ２－ＤＷＡＴＥＲＷＡＶＥＧＥＮＥＲＡＴＥＤＢＹＲＯＣＫＥＲＦＬＡＰＷＡＶＥＭＡＫＥＲ￥ＨｅＷｕ－ｚｈｏｕ（Ｄｅｐｔ．ｏｆＨｙｄｒａｕｌｉｃＥｎｇ．，ＴｓｉｎｇｈｕａＵｎｉｖｅｒｓｉｔｙ，Ｂｅｉｊｉ...     

COMPUTATIONAL RESEARCH ON WAVE MAKING OF MOVING WIGLEY HULL IN TIME DOMAIN

Based on Green＇s theorem, a time domain numerical model was constructed to simulate wave making phenomenon caused by a moving ship. In this article, the Rankine sources and dipoles were placed on boundary surfaces （i.e., the ship surface and free surface）, and a time-stepping scheme was employed. Its unique characteristic is that steady state can be realized from initial value by employing the time-stepping scheme and unsteady free surface conditions. In time domain, if the results of unsteady flow problem tend to data stabilization after many time steps of computation, they could be regarded as the data of steady ones. This model could be employed to steady or unsteady problems. Theoretical reasoning and computational process of this method was described in detail The linear and nonlinear boundary conditions on body surface were studied, and the relative means to realize these boundary conditions in iterative computation were also discussed. Some proper parameters about the model of the Wigley hull were determined by many numerical tests, and their influences on wave making resistance and wave pattern were discussed. According to the comparison between numerical results and data available in relative references, the method used in this work is proven to be a reliable method in time domain. And the lattice reorganization in every time step computation is a feasible numerical approach.     

摇板式造波机所造二维波的完全非线性解

本文采用边界积分方程的时间步进法对摇板式造波机所造二维波的波形及遥板所受水动力矩求完全非线性解。对于自由面和摇板交点处自由面条件和物面条件的相容性作了专门的考虑。在弱非线性情况下，规则波时域非线性的计算结果与频域二阶解及时域线性解作了比较，验证本文的数值方法是可行的。     

应用时域格林函数方法模拟有限水深中波浪对结构物的作用

该文采用时域内满足自由水面条件的格林函数方法对无限和有限水深中波浪与任意形状三维物体相互作用所产生的绕射和辐射问题进行了理论研究和数值计算。建立了不包含自由水面积分的积分方程,消除了自由项系数。文中计算了各种形状三维物体在无限水深和有限水深情况下所受到的绕射和辐射波浪力,并与解析解以及频域理论进行了对比,结果符合良好,验证了本文所提理论的正确性。