孤立波或波群诱发的港湾振荡研究

发布时间：2018-06-12 11:01

  本文选题：港湾振荡 + Boussinesq模型　； 参考：《大连理工大学》2015年博士论文

【摘要】：港湾振荡是一个在海岸工程领域中较为传统且极其重要的研究方向。国内外很多港口都观测到了明显的港湾振荡现象,显著地影响了港口的高效运行和港内船舶的系泊安全。本文首先介绍了港湾振荡的研究背景和意义,列举了文献中所反映出来的实际港口中发生的港湾振荡事件,总结了这些港湾振荡的特征,并系统地阐述了前人关于港湾振荡的研究内容。然后,介绍了本文采用的数值模型-FUNWAVE2.0,该模型是基于一组完全非线性Boussinesq方程建立的。文中介绍了数值模型的控制方程、数值离散、边界条件以及域内造波理论。随后,通过模拟文献中呈现的物理模型实验,对数值模型用于模拟港湾振荡现象的能力进行了验证。本文在此基础上进行了以下进一步的研究：Sobey (Sobey,2006. Normal mode decomposition for identification of storm tide and tsunami hazard. Coastal Engineering 53,289-301)在其论文中提出了用于计算港口共振频率、共振模态形状和分解由风暴潮和海啸诱发的港湾振荡各模态成分响应幅值的正交模态分解法。作者发现,Sobey提出的正交模态分解法在数值处理全反射边界条件的过程中存在不足,这将会导致正交模态分解法计算得到不精确的港口共振频率和共振模态形状。本文提出镜像方法,对其全反射边界条件的数值处理过程进行改进,并使用三个数值算例对改进的正交模态分解法进行了验证。虽然正交模态分解法用于计算风暴潮和海啸诱发的港湾振荡各模态响应幅值是以线性理论为基础的,本文使用两组数值验证算例对该方法用于分离港内在弱非线性波况下各共振模态响应幅值的适用性进行了研究。使用正交模态分解法,分离了由孤立波诱发的狭长型矩形港内港湾振荡各模态的响应幅值,并系统地研究了不同的入射孤立波波高和不同的港口底坡对港内相对波能分布的影响。研究表明：当入射孤立波波高较小时,港内的共振波能主要集中在最低的几个共振模态,高模态仅占有很小的一部分能量；当入射孤立波波高增大时,港内波能在不同共振模态上的分布趋向于均匀,高模态占有的波能比例增加。在本文给出的入射孤立波波高和港口底坡的变化范围内,对于相同的入射孤立波波高,港口底坡的变化对于港内相对波能在各模态上的分布影响很小。采用完全非线性Boussinesq模型,模拟了双色波群引起的狭长型矩形港湾内的共振现象。文中提出了一个基于最小二乘法的波浪分离程序,将港内的低频波浪成分进一步分解为锁相长波和自由长波。进而研究了港湾处于第一共振模态下锁相长波和自由长波的波幅以及它们相对成分随着短波波长的变化。为了进行对比,也考虑了波群未能诱发港湾发生共振的情况。研究表明：无论港内是否发生共振,锁相长波和自由长波的波幅以及它们相对成分均与短波波长密切相关。针对本文中所研究的港口和短波频率的变化范围,当港内发生最低模态的共振时,锁相长波波幅总是要小于自由长波波幅,但是当平均短波波长大于0.66倍的港口长度时,前者往往要大于后者的一半；当港内未发生共振且平均短波波长大于0.56倍港口长度时,锁相长波波幅往往要大于自由长波波幅。
[Abstract]:The harbor oscillation is a more traditional and most important research direction in the field of coastal engineering. Many ports both at home and abroad have observed the obvious harbor oscillation phenomenon, which greatly influenced the efficient operation of the port and the safety of the mooring of the ships in the port. The harbor Oscillation events in the actual port are reflected, the characteristics of these harbors are summarized, and the previous studies on the harbor oscillation are systematically expounded. Then, the numerical model -FUNWAVE2.0 is introduced in this paper. The model is based on a set of complete non linear Boussinesq equations. The number of the models is introduced. The control equations of the value model, numerical dispersion, boundary conditions and the theory of intra domain wave making. Then, through the physical model experiments in the simulated literature, the ability of the numerical model to simulate the harbor oscillation is verified. On this basis, the following further studies are carried out: Sobey (Sobey, 2006. Normal mode decomposit) Ion for identification of storm tide and tsunami hazard. Coastal Engineering 53289-301) in his paper the orthogonal mode decomposition method for calculating the resonance frequency of the port, the shape of the resonant mode, and the decomposition of the response amplitude of the modal components of the Bay oscillation induced by storm tide and tsunami. The modal decomposition method has shortcomings in the process of dealing with the fully reflected boundary conditions. This will lead to the calculation of the inaccurate resonance frequency and resonant mode shape of the port by the orthogonal modal decomposition method. In this paper, a mirror image method is proposed to improve the numerical treatment process of its total reflection boundary condition, and three numerical examples are used to improve the numerical process. The orthogonal modal decomposition method is verified. Although the amplitude of the response modes of the Bay oscillation induced by the storm tide and the tsunami is based on the linear theory, the applicability of the method is used to separate the resonant modal response amplitude of the weakly nonlinear wave conditions in the port by two sets of numerical examples. An orthogonal modal decomposition method is used to separate the response amplitudes of each mode in a narrow rectangular harbor induced by a solitary wave. The effects of different incident solitary wave heights and different port slopes on the relative wave energy distribution in the port are systematically studied. The resonant wave energy is mainly concentrated in the lowest resonant modes, and the high mode only occupies a small part of the energy. When the incident solitary wave is high, the distribution of the internal wave energy in the different resonant modes tends to be uniform and the proportion of the wave energy in the high mode increases. The incident solitary wave height in this paper and the change of the bottom slope of the port are changed in this paper. For the same incident solitary wave, the change in the bottom slope of the port has little influence on the distribution of the relative wave energy in the port. The full nonlinear Boussinesq model is used to simulate the resonance phenomenon in the narrow rectangular harbor caused by the double color wave group. A wave separation process based on the least square method is proposed in this paper. In order, the low-frequency wave components in the port are further decomposed into phase-locked long wave and free long wave. Then the amplitude of the long wave and the free long wave in the first resonant mode of the harbor and the variation of their relative components along with the short wave wavelengths are studied. It is shown that the amplitude of the phase locked long wave and the free long wave and their relative components are closely related to the wavelength of the short wave regardless of whether there is resonance in the port. When the length of the port with short wave length is greater than 0.66 times the length of the port, the former is often more than half of the latter, and the length of the lock is often greater than the free long wave amplitude when there is no resonance in the port and the length of the mean short wave length is greater than 0.56 times the length of the port.
【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】：U652.3
，

本文编号：2009446