波浪破碎过程周期演化特征的试验研究

发布时间：2018-06-08 21:10

本文选题：谱平均周期 + 跨零点周期　；参考：《大连理工大学》2016年硕士论文

【摘要】：海浪要素(如波高、周期)是工程设计普遍关注的重要环境条件,特别是有效波高和有效周期是至关重要的设计波要素。目前,在海洋工程环境条件推算中盛行利用海浪数值模式计算海浪要素,如国际上流行的数值模型SWAN、WAVEWATCH可直接给出有效波高及与谱相关的特征周期,但由此得到的周期值和实测值之间往往存在很大的偏差。这种差异主要源于对影响波浪发展的各种物理过程参数化的不准确性,波浪破碎就是其中之一,破碎能量损耗是海浪模型能量耗散项中重要的物理机制。由于波浪破碎是极其复杂的物理过程,目前对此过程中能量耗散机制了解仍较少,还有待深入研究,对破碎过程周期的变化情况也缺少系统的研究。针对上述问题,本文根据室内试验,探讨了深水极限波浪破碎及浅水波浪变形破碎过程特征周期的演化规律。第二章中,首先给出了极限波浪的生成方法-波能聚焦法,在实验室二维水槽中生成不同参数的深水聚焦波和破碎波,研究了聚焦波和破碎波波面的演化特性,重点分析了各种特征周期的演化规律。另外,还研究了频谱分布形式、频率宽度对周期演化的影响；在第三章中,首先介绍了试验地形设置,在实验室水槽中布置一坡度为1：15的斜坡平台地形,进行规则波和不规则波在斜坡平台上传播变形的试验,研究波浪在浅水中传播变形特征,重点分析各种特征周期的演化规律,并分析了入射波周期对波浪周期演化的影响；第四章中,总结了表征波浪非线性作用及破碎强度的参数,分析波浪非线性传播破碎后周期变化率与这些特征参数的关系,并通过最小二乘法拟合给出相应的关系式。本文通过物理模型试验,对深水极限波浪破碎、浅水波浪破碎过程周期的演化特征进行了分析,并探讨了周期变化率与表征波浪破碎强度或非线性的特征参数的关系,研究成果可为海洋工程设计和数值模型的改进提供依据。
[Abstract]:Wave elements (such as wave height and period) are important environmental conditions of engineering design, especially the effective wave height and effective period are the most important design wave elements. At present, ocean wave numerical model is widely used to calculate ocean wave elements in the calculation of marine engineering environmental conditions. For example, Swann WAVEWATCH, a popular international numerical model, can directly give the effective wave height and characteristic periods related to the spectrum. But there is often a big deviation between the period value and the measured value. The difference is mainly due to the inaccuracy of parameterization of various physical processes affecting wave development, among which wave breakage is one of the most important physical mechanisms of energy dissipation in wave model. Because wave breakage is an extremely complex physical process, the mechanism of energy dissipation in this process is still less understood, which needs to be further studied, and the variation of the period of breaking process is also lack of systematic research. In view of the above problems, based on the laboratory tests, this paper discusses the evolution law of the characteristic periods of the deep water limit wave breakage and the shallow water wave deformation breakage process. In the second chapter, the method of wave energy focusing, which is the generation method of limit wave, is first given. Different parameters of deep water focused wave and broken wave are generated in the laboratory two-dimensional flume, and the evolution characteristics of focused wave and broken wave surface are studied. The evolution law of various characteristic periods is analyzed in detail. In the third chapter, the experimental terrain setting is introduced, and a slope platform terrain with a slope of 1:15 is arranged in the laboratory tank. The propagation and deformation characteristics of regular and irregular waves in shallow water are studied, and the evolution laws of various characteristic periods are analyzed, and the influence of incident wave periods on wave periodic evolution is analyzed. In chapter 4, the parameters that characterize the nonlinear action and breaking strength of waves are summarized, and the relationship between the rate of periodic change and these characteristic parameters after wave nonlinear propagation breaking is analyzed, and the corresponding relationship is obtained by least square method. In this paper, through physical model tests, the evolution characteristics of the cycle of wave breaking in deep water and shallow water are analyzed, and the relationship between the rate of periodic variation and the characteristic parameters that characterize the breaking strength or nonlinearity of waves is discussed. The research results can provide the basis for the improvement of ocean engineering design and numerical model.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P731.22;P75

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