孤立波作用下海堤越浪实验研究

发布时间：2018-03-28 22:35

本文选题：孤立波　切入点：海堤　出处：《上海交通大学》2014年硕士论文

【摘要】：海啸、风暴潮等海洋类灾害近年来时有发生，给人类沿海地区的生产和生活带来极大的破坏。海堤作为重要海岸防护工程建筑物，，是保护沿海地区抵御灾害的重要屏障，目前沿海地区最为常用的海堤结构类型即为斜坡式的海堤。从大量海洋灾害造成的海堤破坏案例来看，海堤越浪是造成海堤破坏最为主要的原因之一。海啸等浅水大波冲击海堤，越过堤顶，冲刷堤顶和后坡，破坏海堤的结构和稳定。自上个世纪起，国内外不少学者就开始对波浪作用下海堤的越浪量和越浪流的情况进行研究，取得了一定成果，但对孤立波的越浪情况研究不多。本文针对不同形式的海堤模型，主要研究了孤立波作用下，海堤越浪水动力特性。针对简单堤断面，在不同堤前水深和相对波高下，进行一系列物理模型实验，主要分析了海堤的越浪量，堤顶越浪水体流态和波压，堤顶流场分布和堤顶越浪流流速和厚度等。孤立波越浪量随来波相对波高的增大而增加，随着堤顶相对超高的减小呈指数增大。基于越浪量实验数据建立了斜坡堤上孤立波越浪量的经验预报公式，与以往的研究成果进行对比，验证了公式的有效性。在不同工况下，进行孤立波堤顶流场的PIV测量。研究了堤顶越浪水体的形态、波压和流场分布等的变化规律，并且给出了细致的流场结构。堤顶越浪流的PIV测量结果表明，堤顶越浪流最大垂线平均流速沿程增加；在同种水深同一位置处，其垂线平均流速最大值随着相对波高的增大而增大；堤顶越浪流厚度沿程减小，随着传播的进行减小的速度变缓；堤顶最大波压出现在堤顶前缘且沿程减小。基于PIV测量结果得到孤立波越浪量与越浪量的直接测量结果进行对比，两者一致性较好验证了PIV测量方法的可行性和有效性。针对复合堤模型，采用高速摄像技术和流动显示技术，主要分析在同种水深不同相对波高下，堤顶越浪水体的形态和堤顶波压的变化情况。随着相对波高的增加，堤顶越浪流的变化更加剧烈，最大波压也随之增加，且最大波压出现位置向后坡方向移动。
[Abstract]:Tsunami, storm surge and other marine disasters have occurred frequently in recent years, which bring great damage to the production and life of human coastal areas. As an important coastal protection engineering building, seawall is an important barrier to protect coastal areas from disasters. At present, the most commonly used type of seawall structure in coastal areas is sloping seawall. Wave surpassing is one of the most important causes of breakwater damage. Large waves of shallow water, such as the tsunami, hit the seawall, crossed the top of the embankment, washed the top and back slope of the seawall, and destroyed the structure and stability of the seawall. Many scholars at home and abroad have begun to study the surpassing quantity and current of seawall under the action of waves, and have obtained some achievements, but there are few researches on the surpassing of solitary waves. In this paper, we focus on different types of seawall models. The dynamic characteristics of seawall surfacing under the action of solitary wave are studied. In this paper, a series of physical model experiments are carried out under different water depth and relative wave height in front of the simple embankment. The surpassing quantity of the seawall, the water flow pattern and the wave pressure at the top of the seawall are analyzed. The flow field distribution at the top of the embankment and the velocity and thickness of the surpassing wave flow at the top of the embankment increase with the increase of the relative wave height of the incoming wave. Based on the experimental data of surpassing wave volume, the empirical prediction formula of solitary wave overtaking on slope embankment is established, which is compared with the previous research results, and the validity of the formula is verified. The PIV measurement of the flow field at the top of the isolated wave breakwater is carried out. The variation law of the water form, wave pressure and the distribution of the flow field are studied, and the detailed flow field structure is given. The PIV measurement results of the surpassing wave flow at the top of the breakwater show that, The average velocity along the maximum vertical line of the top of the embankment increased; at the same position of the same water depth, the maximum velocity of the vertical line increased with the increase of the relative wave height, and the thickness of the surpassing wave flow at the top of the embankment decreased along the course. The maximum wave pressure on the top of the breakwater appears at the front edge of the top of the embankment and decreases along the path. Based on the PIV measurement results, the direct measurement results of the solitary wave overtaking and surpassing wave are compared. The consistency between the two methods verifies the feasibility and effectiveness of the PIV measurement method. In view of the composite embankment model, high speed camera technique and flow display technique are used to analyze the changes of the water shape and the wave pressure at the top of the embankment under different relative wave heights of the same water depth, with the increase of the relative wave height. The change of the surpassing wave flow at the top of the embankment is more intense, the maximum wave pressure also increases with it, and the position of the maximum wave pressure moves back to the slope direction.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U656.314

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