多向不规则波浪与大尺度群墩作用的研究

发布时间：2018-02-16 01:45

本文关键词： 多向不规则波方向分布群墩波浪荷载耦合模型　出处：《大连理工大学》2015年博士论文　论文类型：学位论文

【摘要】：群墩结构是海岸及海洋工程建筑物的典型结构,通常由一系列大尺度墩柱(墩柱直径D与波浪波长λ之比D/λ=0.15)组成。随着对海洋资源的进一步开发,越来越多的离岸建筑物采用群墩结构的形式,例如跨海大桥和海上风机的基础、海上钻井平台和浮式机场等。而波浪是海洋工程结构物上的主要荷载,因此精确计算波浪对群墩结构物的作用对于工程设计具有重要的意义。然而,目前的研究和工程设计规范大多考虑的是单向波浪,而在实际的海洋中,波浪是多向不规则的,其能量不仅分布在一定的频率范围内,而且分布在相当宽的方向范围内。波浪的方向分布对于海浪预报、波浪绕射和折射、波浪作用下泥沙运动以及波浪对建筑物的作用等都具有较大的影响。因此,对多向不规则波浪与群墩作用的研究具有重要的现实意义和应用价值。物理模型实验是研究多向不规则波浪与群墩作用的重要方法。本文首先详细的介绍了多向不规则波浪与群墩作用的实验布置以及实验过程,然后通过模型实验系统地研究了多向不规则波浪与大尺度墩柱作用时的波浪荷载。通过对波浪荷载的时间过程线进行统计分析得到了作用在墩柱上的正向力、横向力和爬高。当入射波浪为单向波浪时,由于墩柱两侧的波压力差为零,并不会出现横向力。但是当波浪为多向波时,由于波浪的能量分布在一定的方向范围内,波浪的波峰线较短且是随机的,此时墩柱两侧的波压力差不恒为零,因此出现了横向力。横向力受波浪方向分布的影响比正向力显著,随着方向分布集中度参数s的减小,即波浪的方向分布宽度逐渐增大,作用在墩柱上的横向力明显增大。波浪的方向分布对墩柱表面上的爬高也有一定的影响,最大爬高发生在圆柱迎浪面的最前点,但是最小点的位置却随着方向分布集中度参数而发生变化,当s较小,即方向分布较宽时,a=180°处的爬高最小,当s较大时,a=135°处爬高最小同时,本文基于波浪与群墩作用的线性理论,通过传递函数的方法,建立了多向不规则波浪与大尺度墩柱及群墩结构作用的计算方法。通过计算和实验结果的对比,对该计算方法进行了验证。进一步计算研究了多向不规则波浪与大尺度墩柱及群墩的作用。多向不规则波浪与群墩结构作用时,随着方向分布宽度的变大,波浪场中大多数位置处的波高与单向不规则波浪作用结果的比值都随之变大,部分位置可增加50%。波浪的方向分布对群墩结构所受波浪力也有明显的影响,对于串列群墩,由于波浪方向分布的原因,最大横向力一般发生在后排的墩柱上。这与单向波浪作用时的结果是完全不同的,在实际的工程设计中需予以注意。同时对常用的群墩系数进行了研究,给出了不同布置形式群墩结构的群墩系数。此外,波浪俘获现象不仅在规则波作用下会发生,在多向不规则波浪作用时也会发生,使得墩柱所受波浪荷载明显变大。进一步,为了考虑波浪非线性的影响,本文采用基于OpenFOAM建立的数值波浪水池来模拟多向不规则波浪与大尺度墩柱的作用。针对基于求解Navier-Stokes方程的OpenFOAM波浪水池在模拟多向不规则波浪时计算量较大、速度较慢的缺点,本文采用势流理论与OpenFOAM建立了耦合的数值计算方法,该方法可以减少OpenFOAM波浪水池的计算量、提高计算效率。并采用耦合模型模拟了多向不规则波浪与大尺度墩柱的作用,数值模拟得到的作用在墩柱上的波浪力和爬高与实验值更接近。
[Abstract]:Pier group structure is a typical structure of coastal and ocean engineering structures, usually consisting of a series of large scale cylinder (pier diameter D and the ratio of D/ wave wavelength lambda =0.15). With the further development of marine resources, offshore building more and more in the form of pier group structure, such as the foundation of the bridge and offshore wind turbines, offshore drilling platforms and floating airport. The wave is the main load of ocean engineering structures, therefore accurate calculation of wave on pier group structure has important significance for the engineering design specification. However, most of the current research and engineering design consideration is the one-way wave, and in the actual in the ocean, the waves are multidirectional and irregular, not only the energy distribution in a certain frequency range, and distributed in a wide range. The direction of wave direction distribution for wave forecast, wave diffraction and refraction Under the action of waves, sediment movement and the effect of waves on buildings are of great influence. Therefore, the research of multi-directional irregular wave and the effect of pier group has important practical significance and application value. The physical model experiment is an important method to study the multi-directional irregular wave and pier group role. This paper first described in detail the experimental arrangement of multi-directional irregular wave and pier group effect and experiment process, and then through the model experiment system of wave loading multidirectional irregular waves and large scale pier column. Through statistical analysis of wave load time curve obtained positive force in the pier, lateral force and climbing when the incident wave is one-way wave, the wave pressure on both sides of the pier is almost zero, and no lateral force. But when the waves for multi wave, the wave energy distribution in A certain direction, the wave crest line is short and random, the wave pressure difference on both sides of the pier is not identically zero, so there was a lateral force. The transverse force is affected by the distribution of wave direction than positive force significantly, with the decrease of s concentration distribution parameters, namely the wave direction the distribution width increases gradually, lateral force on the pier increases obviously. Also has some influence on the pier surface on the distribution of wave runup in the direction of maximum run-up occurred yinglang in the cylindrical surface of the front, but the minimum position but with the direction of distribution of moderate change parameters set, when s is small that is, the direction of the wide distribution, a=180 degrees at minimum climb, when s is large, a=135 DEG climbing at the minimum, the linear theory of wave and pier group based on action, through the transfer function method, a multi-directional irregular wave with large scale cylinder The calculation method and the structure of pier group effect. Through the comparison between the calculated and experimental results, the calculation method was verified. Further studied effects of multidirectional irregular waves and large scale pier and pier group. The multi-directional irregular wave and pier group structure, with the direction of distribution width became larger the ratio at most locations in the wave field of wave height and unidirectional irregular wave action results become bigger, some position can increase 50%. wave direction distribution of pier group structure by wave force also has obvious implications for the tandem pier group, due to the distribution of wave direction, the maximum lateral force generally occurs in the the back of the pier. This one-way wave action and the result is completely different, and should be paid attention to in the actual engineering design. At the same time on the pier group coefficients are studied, given the different layout of pier group The coefficient of pier group structure. In addition, the wave trapping phenomenon not only in regular waves will happen, will happen in irregular wave action, the pier under wave load was significantly larger. Further, in order to consider the influence of non-linear wave, the numerical wave tank based on OpenFOAM to simulate the multi-directional regular waves and large scale pier. According to OpenFOAM wave based on the Navier-Stokes equation in the simulation of multi-directional irregular wave when the large amount of calculation, the slow speed, the potential flow theory and OpenFOAM established a coupling numerical method used in this paper, the method can reduce the amount of calculation of OpenFOAM wave, improve the computational efficiency and the coupling model to simulate the multidirectional irregular waves and large scale pier, by numerical simulation on pier column wave force and climbing and The experimental value is closer.

【学位授予单位】：大连理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：P731.22;P75

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