固壁附近水平圆柱在波浪水流共存场中的流动显示及水动力特征

固壁附近的水平的圆柱体在波浪、波流作用下的受力情况与其周围的流场状态密切相关。为探讨圆柱形成的机理，应当对流场的涡结构有充分的认识，受力过程与记演化过程的同步分析万为重要。本文通过实验研究并对比数值分析的结果，对波浪、波流场中圆柱体受力与流场状态的关系做一初步讨论。     

Derivation of Reliability Index Vector Formula for Series System and Its Application

In this study, a reliability index vector formula is proposed for series system with two failure modes in term of the concept of reliability index vector and equivalent failure modes. Firstly, the reliability index vector is introduced to determine the correlation coefficient between two failure modes, and then, the reliability index vector of a series system can be obtained. Several numerical cases and an analysis on offshore platform are performed, and the results show that this scheme provided here has better computational accuracy, and its calculation process is simpler for the series systems reliability calculations compared with the other methods. Also this scheme is more convenient for the engineering applications.     

基于模糊影响图的海洋结构风险分析方法研究

基于模糊影响图(FPID)和失效模式与效果分析(FMEA)建立了一种海洋结构风险分析方法。鉴于风险分析中某些事件发生概率和关系概率两个重要参数确定时需借助专家主观判断,本文将模糊概率的概念引入海洋结构影响图评估方法中。该方法成功地应用到海洋平台人员伤害分析中。虽然这里仅给出了该方法在海洋平台风险评估中的应用,但其具有更广泛应用价值。     

An Intelligent Method for Structural Reliability Analysis Based on Response Surface

As water depth increases, the structural safety and reliability of a system become more and more important and challenging. Therefore, the structural reliability method must be applied in ocean engineering design such as offshore platform design. If the performance function is known in structural reliability analysis, the first-order second-moment method is often used. If the performance function could not be definitely expressed, the response surface method is always used because it has a very clear train of thought and simple progranuning. However, the traditional response surface method fits the response surface of quadratic polynomials where the problem of accuracy could not be solved, because the true limit state surface can be fitted well only in the area near the checking point. In this paper, an intelligent computing method based on the whole response surface is proposed, which can be used for the situation where the performance function could not be definitely expressed in structural reliability analysis. In this method, a response surface of the fuzzy noural network for the whole area should be constructed first, and then the structural reliability can be calculated by the genetic algorithm. In the proposed method, all the sample points for the training network come from the whole area, so the true limit state surface in the whole area can be fitted. Through calculational examples and comparative analysis, it can be known that the proposed method is much better than the traditional response surface method of quadratic polynomials, because, the amount of calculation of finite element analysis is largely reduced, the accuracy of calculation is improved, and the true limit state surface can be fitted very well in the whole area. So, the method proposed in this paper is suitable for engineering application.     

互相关技术在海洋工程中的应用研究

随着计算机技术和图像处理技术的快速发展，互相关技术在近几十年取得了很大发展，已成为当今工程领域的一项重要测试技术。本文详细阐述了互相关技术的基本原理，通过实例说明了互相关技术在海洋工程领域中的实际应用，充分说明了该技术的实用性与可靠性，并简要介绍了互相关技术在其它工程领域中的应用情况。     

波谱浅水变形的数值计算及试验研究

用计算方法得到浅海波浪谱,对于浅水海域上建筑物的设计计算及动力分析都具有极其重要的意义。当波浪传播时,由于水深变浅、海底摩擦及反射、内部紊动摩擦、折射与海底渗透等因素的影响,波浪能量要有所变化。但此过程极其复杂。国内外学者对此作了大量研究工作,尚未得到一个较为统一的计算方法。本文将从波能流守恒这一基本原理出发,首先通过计算得到各组成波的浅水变形,然后再利用波浪叠加法得到波浪的浅水谱。文中还对能量损失项的计算采用了几种不同的算法,并把各计算值与试验结果进行了比较分析,提出了一些初步看法与结论,可供计算时参考应用。     

Numerical Investigation on Submerged Horizontal Plate

Hydrodynamic characters on a horizontal, thin, rigid plate located beneath the free surface are numerically investigated. Assuming a linear, time-harmonic potential flow and utilizing Green identity, the governing Laplace equation can be simplified into Fredholm integral equation ofthe second kind. Supposing linear-order discontinuous elements along intersecting vertical boundaries, and by use of the boundary element method, numerical solution about source strength distribution on the plate can be changed into a series of algebraic equations. The 3D Green function is introduced to set up the integral equations, and the GMRES solver is performed for solving the large dense linear system of equations. The added-mass, damping force and exciting force are evaluated directly from the equations. It is found that the added-mass coefficient becomes negative for a range of frequencies when the plate is sufficiently close to the free surface.     

粉沙海床管道在联锁排防护下的冲刷试验研究

采用当地海床的天然粉沙进行试验床面的设计,对海底管道在实际海床受到的极限波浪和最大水流作用进行试验,在管道上方铺设混凝土联锁排,对联锁排块体稳定性和其对管道防护的有效性进行研究。通过物理模型试验,研究了在极限波浪和最大水流作用下,管道在粉沙床面最大冲刷深度。通过不同水深中波流条件下研究了混凝土联锁排防护效果及其周围床面的冲刷变化,观测了联锁排的稳定性。试验结果表明:按半经验半理论简化公式得出的联锁排厚度能满足稳定性的要求,比水利部规范计算的联锁排厚度偏大的公式更加适合应用,试验期间混凝土联锁排的排面稳定,能有效保护管道,在该防护下管道没有冲刷,只在联锁排上下游与床面接触的来流段和尾端有冲刷,但该冲刷深度不影响联锁排整体的稳定性。     

Derivation of reliability index vector formula for series system and its application

In this study, a reliability index vector formula is proposed for series system with two failure modes in term of the concept of reliability index vector and equivalent failure modes. Firstly, the reliability index vector is introduced to determine the correlation coefficient between two failure modes, and then, the reliability index vector of a series system can be obtained. Several numerical cases and an analysis on offshore platform are performed, and the results show that this scheme provided here has better computational accuracy, and its calculation process is simpler for the series systems reliability calculations compared with the other methods. Also this scheme is more convenient for the engineering applications.     

海上风力发电机三桩基础波流力的计算

考虑了波浪在水流中的变形,计算了波流共存场中海上风力发电机三柱基础的受力.应用离散涡法,求解了不可压缩粘性流体的水平二维涡量-流函数Navier-Stokes方程,模拟了不同桩位布置对波流场的影响.以及各桩受力和三桩基础总力的随布置方式不同的变化.