高速双体船斜浪中运动响应及连接桥波浪载荷预报

应用二维时域格林函数法对二维半定解问题进行了求解,应用发展的二维半理论和程序对WP60高速穿浪双体船在斜浪中的垂荡、纵摇、横摇和垂向加速度等运动响应及连接桥结构的波浪载荷进行预报,并把理论计算结果与模型试验结果及其它程序计算结果比较分析,初步验证了文中方法和程序在预报高速双体船运动及载荷性能中的适用性.     

二维物体上的二阶波浪力

近年来,作用于固定式或浮式海洋结构物上的非线性波浪力正在引起广泛的注意。本文处理了规则波对固定的二维物体的二阶非线性影响,协调地求得了二阶绕射势,并进而得到了二阶定常波浪力和二阶倍频波浪力。 借助于切片理论,此方法和结果似也可用来预估船舶或某些半潜平台的二阶波浪作用力和二阶运动。     

潜水器水下拖带航行运动响应数值计算与性能分析

基于三维势流理论,采用多体水动力学分析技术,使用典型的格林函数法求解波浪力,对耦合拖缆的潜水器水下拖带航行进行频域与时域数值模拟计算,分析波浪周期、浪向角、拖缆形态、拖缆长度等因素对水下拖航过程中潜水器拖缆张力,以及纵摇、横摇、横荡等运动响应的影响,为潜水器水下拖航系统设计提供参考。     

波浪中船舶操纵横摇预报及舵效影响分析

基于经典MMG模型建立操纵性和横摇四自由度耦合模型,并利用耦合模型叠加波浪力的方式,论文对一艘S175自航船模进行波浪中操纵性和横摇预报,并根据自航模试验进行对比验证;其波浪力采用三维面元法计算,并根据船舶实时速度和遭遇浪向进行二维插值。在验证模型准确性后,对船舶在不同舵速、浪向角下的操纵运动进行时域模拟,比较了舵速和遭遇浪向对船舶舵效的影响,分析了浪向、波频对船舶操纵和回转时横摇的影响。     

潜体近水面波浪力计算的数值方法

潜体近水面航行时将受到波浪力的作用，其中二队垂向平均力和二阶纵摇平均力 可能使潜体浮出水面因此正确估算作用在潜体上的二阶平均波浪力，对近水面航行的潜体十分重要。本文利用浪浪上任意低航速三物体波浪力的计算方法来计算近水面体的波浪力并与国际上球结果，试验结果相比比较吻合，说明了本方法的实用性。     

小水线面双体船在波浪中的水动力计算

采用直接边界元法,利用三维移动脉动源格林函数计算小水线面双体船在波浪中的水动力.针对小水线面双体船在零航速、横浪时所受到的波浪载荷最大的特点,分析计算了横浪和斜浪工况下水动力大小和分布特性.     

粘性对方尾船波浪力的影响分析

航行船舶绕射问题的准确求解是预报船舶波浪中运动的基础.文章分别采用基于三维移动脉动源的边界元法和基于RANS方程的CFD方法求解了规则波中航行的方尾船模型的波浪力,并通过与试验结果比较验证了方法的可靠性.CFD计算时通过从波浪力中分离出粘性力,研究了粘性对方尾船波浪力的影响.结果表明,基于RANS方程的波浪力计算结果与试验结果和势流理论结果吻合良好,在长波中与试验值更接近.粘性对船模斜浪航行时的横摇力矩有较大影响.     

粘性对方尾船波浪力的影响分析（英文）

航行船舶绕射问题的准确求解是预报船舶波浪中运动的基础。文章分别采用基于三维移动脉动源的边界元法和基于RANS方程的CFD方法求解了规则波中航行的方尾船模型的波浪力,并通过与试验结果比较验证了方法的可靠性。CFD计算时通过从波浪力中分离出粘性力,研究了粘性对方尾船波浪力的影响。结果表明,基于RANS方程的波浪力计算结果与试验结果和势流理论结果吻合良好,在长波中与试验值更接近。粘性对船模斜浪航行时的横摇力矩有较大影响。     

半潜式钻井平台波浪散射力与运动响应分析

文章对半潜式钻井平台(Semi-Submersible)在波浪作用下的散射波浪力和运动响应进行了分析研究,研究中采用了基于波浪辐射、绕射理论的三维有限水深格林函数方法.为了保证这种大型复杂海工结构物计算结果的高精度,研究中对于边界积分方程的离散求解采用了考虑几何对称性的高阶边界元算法.通过对计算结果的比较分析,对这种型式的钻井平台的波浪力和运动响应有了一个全面的认识,对结构设计有很好的参考价值.     

五体船波浪载荷计算研究

基于势流理论和格林函数,探索五体船在不规则波中运动的波浪载荷响应函数,并且运用波谱分析法,采用北大西洋波浪散布图,对船体的几个典型剖面作波浪载荷的长期预报。分析不同航速、不同浪向角下典型剖面上的弯矩和剪力,研究五体船在波浪中运动时剖面载荷的分布规律。     

Nonlinear wave forces on large-scale submerged tunnel element

This paper presents parametric studies of nonlinear wave forces on large-scale submerged tunnel element. A transportation project of submerged tunnel element under irregular wave conditions is taken as the research background. Three-dimensional diffraction potential and radiation potential associating with the motion of the floating body are utilized, and an efficient three dimensional Green function is implemented to solve the radiation-diffraction problem. A computational method for calculating the nonlinear wave forces of the submerged tunnel element is developed. The present method is validated by the existed methods and experimental data, and good agreements are observed for all test models. The effects of wave parameters and structural parameters on the second-order nonlinear wave forces are studied. Results from the present study can provide valuable recommendations for the weather window and downtime frequencies, the configuration of tugboats, the arrangement of sea-route, and the size and type of the design and construction of the submerged tunnel element.     

内孤立波作用下水下潜器的载荷特性数值分析

为了研究海洋内孤立波作用下潜器的载荷特性,以RANS方程为控制方程,依据Kdv,eKdv和mKdv三类内孤立波理论计算速度入口,建立两层流体中内孤立波与水下潜器相互作用的数值模拟方法,计算分析内孤立波作用下潜器的水平力、垂向力和力矩的变化规律.结果表明,数值模拟得到的内孤立波波形及振幅与其对应理论解和文献中实验结果吻合良好.潜器的受力变化规律与内孤立波波幅、上下层水深比和潜器潜深有关.     

近水面潜艇波浪力计算研究评述

对潜艇波浪力计算的研究现状进行了小结。分析了近水面潜艇波浪力计算的几种有代表性的研究方法,如切片法、STF理论、源汇分布法、面元法、Frank源分布紧密拟合法及其组合方法等的具体应用。讨论了目前潜艇波浪力研究中存在的一些问题,尤其是二阶波浪力的非线性特性、潜艇运动扰动及其相互耦合的影响还不清楚,已建立的理论和方法尚不能满足工程实际的需要。最后提出了近水面航行潜艇所受波浪力计算中有待深入研究的重点问题。     

直立圆柱体内孤立波载荷特性数值模拟

以三类内孤立波理论(KdV、eKdV和MCC)的适用性条件为依据,将内孤立波诱导上下层深度平均水平速度作为入口条件,采用Navier-Stokes方程为流场控制方程,建立了两层流体中内孤立波对直立圆柱体强非线性作用的数值模拟方法.结果表明,数值模拟所得内孤立波波形及其振幅与相应理论和实验结果一致,并且直立圆柱体内孤立波水平力、垂向力及其力矩数值模拟结果与实验结果吻合.直立圆柱体内孤立波载荷由波浪压差力、粘性压差力和摩擦力构成,其中摩擦力很小,可以忽略;对于水平力,其波浪压差力与粘性压差力量级相当,流体粘性的影响显著;对于垂向力,粘性压差力很小,流体粘性影响可以忽略.此外,直立圆柱体对内孤立波的波形及其诱导流场的影响很小,因此采用Morison公式和傅汝德—克雷洛夫力分别计算其内孤立波水平力和垂向力是可行的.     

Simplified analysis for estimation of the behavior of a submerged floating tunnel in waves and experimental verification

To achieve rational design in waves for a submerged floating tunnel which has emerged as a new offshore transportation infrastructure, it's necessary to understand its hydrodynamic behavior. For simple but accurate estimation of hydrodynamic forces, a theoretical method is proposed and the tests with physical models in a wave flume were carried out for verification. Morison's equation was used to estimate wave loads composed of inertia force and drag force. Forces calculated by applying the linear wave theory to Morison's equation coincided well with those measured by the tests. The test results showed that mooring systems played a significant role in the movement of the submerged floating tunnel in waves. A pendulum model could be used to describe the motion of the submerged floating tunnel with a single vertical mooring. Based on the verified relations, a simple slack condition which causes the submerged floating tunnel to be unstable was also proposed. The simplified approach proposed by this study proved to be useful in designing the submerged floating tunnel in the initial stage.     

Second-order wave run-up on a vertical cylinder adjacent to a plane wall based on the application of quadratic transfer function in bi-directional waves

A numerical model was developed in this study to simulate the wave diffraction caused by an arbitrarily shaped structure in the presence of bi-directional incident waves based on a higher-order boundary element method (HOBEM). Based on the developed model, the wave elevation quadratic transfer function (QTF) in bi-directional waves, which is defined as the second-order wave elevation caused by two incident waves of unit amplitude from two directions, can be determined. The developed model was subsequently used to investigate the wave interaction with a cylinder situated near a vertical wall. The image principle was applied to transform the original problem into an equivalent one of wave diffraction caused by two symmetrical cylinders in open seas exposed to bi-directional incident waves. The second-order wave run-up on the cylinder can then be determined using the wave elevation QTF obtained from an analysis of the equivalent problem. A detailed numerical analysis was then conducted. Numerical results revealed that the presence of the vertical wall can apparently disturb the wave diffraction process from the cylinder, and lead to significantly amplified second-order wave elevation within the region between the wall and cylinder. In addition, the respective contribution from the first- and second-order components to the overall wave elevation around the cylinder was discussed.     

Three-dimensional numerical wave tank simulations on fully nonlinear wave–current–body interactions

A finite-difference scheme and a marker-and-cell (MAC) method are used for numerical wave tank (NWT) simulations to investigate the characteristics of nonlinear wave motions and their interactions with a stationary three-dimensional body in the presence of steady uniform currents. The Navier–Stokes (NS) equation is solved in the computational domain, and the boundary values are updated at each time-step by a finite-difference time-marching scheme in the frame of a rectangular coordinate system. The fully nonlinear kinematic free-surface condition is satisfied by the marker–density function technique developed for two fluid layers. The incident waves are generated from the inflow boundary by prescribing a velocity profile resembling the motions of a flexible flap wavemaker, and the outgoing waves are numerically dissipated inside an artificial damping zone located at the end of the tank. Using the NS–MAC NWT, nonlinear wave and current interactions around a stationary vertical truncated circular cylinder are studied, and the results are compared with the experimental results of Mercier and Niedzwecki, a time-domain NWT based on linear potential theory, a fully nonlinear NWT, and a second-order diffraction computation. Received: July 3, 2001 / Accepted: September 25, 2001     

潜式沉箱-群桩-平台型复合结构波浪力计算的试验研究

文章介绍了一种潜式沉箱、群桩和平台相结合的新型复合结构.通过物理模型试验对这种复合结构在规则波和不规则波作用下的水动力特征进行了研究,探讨了正向波浪总力和垂向波浪总力与无因次参数相对波高H/d、相对沉箱长度A1/L及相对沉箱潜深d1/L之间的关系.根据试验结果总结出正向力与垂向力的计算公式,给出了复合结构各部分受力随透...     

考虑定常兴波影响的辐射问题去奇Rankine源方法数值计算

随着中高速船舶在海洋资源开发中的广泛应用,航速对船舶在波浪中摇荡运动的影响受到重视。本文基于势流理论,采用非均匀有理B样条(NURBS)表达物面,应用去奇Rankine源方法求解流场速度势;推导了兴波问题的二阶近似非线性自由面边界条件,以及考虑二阶近似非线性兴波影响的辐射速度势的线性自由面和物面边界条件。本文编程首先数值计算了Wigley船型的近似非线性兴波问题,将计算的线性和非线性兴波阻力系数与文献结果做了比较;然后数值计算了计及线性定常兴波影响的下潜圆球有航速辐射问题,将计算的附加质量和阻尼系数与文献结果比较。本文计算结果与文献结果吻合程度较好,验证了本文数值计算方法的有效性。文中还给出了兴波波形和辐射波形。