防波堤

It is because breakwater has its advantages on engineering cost、construction and influence to circumstance, comparing with entity breakwater.

这是因为从工程造价、施工以及对环境的影响等方面，透空式防波堤都要优于实体式防波堤。

The quarter circular breakwater is a new type breakwater developed on the basis of the semi-circular breakwater.

圆弧面防波堤是在半圆形防波堤基础上开发的一种新型防波堤。

So a new type quarter-circularbreakwater is brought forward.As the same weight as semi-circular breakwater,quarter-circular breakwater bottom length is reduced to decrease jackstone.

为此，提出一种圆弧面(1/4圆)防波堤的新堤型，在与半圆型防波堤断面自重相近时，尽可能减窄底宽，从而减少大量抛石基床的数量。

The main results can beexpressed as follows:(1)Based on πtheory, some affected factors about wave forces are given, and therelation between affected factors and wave forces is analysised by experimentalresults.(2) The distribution of wave press at representative time and reflection nature aregiven and their variety charactes are discussed by experimental results.(3)By comparing the wave forces of quarter-circular breakwater and semi-circularbreakwater under the same wave conditions,some approximately wave forcesexpressions of quarter-circular breakwater are given.(4)Based on VOF method to trace water free surface,solve numerical value ofRANS equation,and get the distributions of flow field and wave press ofquarter-circular breakwater at the same time during one period,the mechanism ofwave force is also discussed elementarily.(5) Based on the result that RANS equation of numerical simulation agree wellwith experimental results,a new approach to study hydraulic natures of quarter-circular breakwater is provided.

其主要结论如下：一、通过π定理，确定影响波浪力的无因次参变量，根据试验结果对其影响因素进行分析；二、基于模型试验，给出典型时刻圆弧面防波堤的同步波压分布和反射特性，讨论它们的变化特点；三、通过相同条件下圆弧面防波堤与半圆型防波堤两种堤型试验波浪力的比较，给出了圆弧面防波堤波浪力的近似方法；四、利用VOF法追踪自由水面，数值求解RANS方程，得到圆弧堤堤体周围的流场和压力场，初步分析了速度涡流与压力场的相互影响；五、对比数值分析与试验结果，探讨数值方法研究圆弧面防波堤水力特性的可行性，提供新的研究途径

An original Jarlan-type perforated wall breakwater consists of a perforated front wall, a solid back wall and a wave absorbing chamber between them. In practice, the Jarlan-type perforated breakwaters are usually constructed with perforated caissons.

Jarlan型开孔墙式防波堤的基本结构形式包括前开孔直立墙、后实体墙以及前后墙之间的消浪室，在工程应用中经常是将沉箱的前墙开孔，建成开孔沉箱式防波堤。

A series of irregular wave experiments on chamfered vertical breakwater were carried out to obtain the statistical characterization and the uncertainty coefficients for wave force.

通过不规则波浪的物理模型实验，给出了作用在削角防波堤波浪力不确定性系数及其统计特征，提出了适合削角防波堤的合田良实修正公式，并明确了不规则波条件下破碎波对削角堤作用特点。

In the recent years, in order to diminish the wave reflection and the wave force, many countries have conducted researches to study new type of breakwaters instead of the solid conventional structure.

随着港口和海岸防护技术的发展，传统的直立式防波堤已不能满足工程实际的需要，近年来各国竞相研究各种新型的防波堤结构，以减小波浪反射和结构受力，并降低工程造价。

Many researchers have investigated the interaction of water waves with Jarlan-type perforated wall breakwaters. But, due to the complexity of this problem, the previous studies are still not sufficient.

已经有许多学者对波浪与开孔墙式防波堤的相互作用进行了研究，但是，开孔墙式防波堤的消浪机理十分复杂，这其中仍存在大量亟需解决的问题。

For the four types of possible motions of caisson breakwaters, a dynamic analysis model of caisson breakwaters under breaking wave impact is founded and a numerical method is presented, which can be used to simulate the motions of caisson breakwaters. A small scale model test is designed, which can be used to examine the dynamic analysis model and numerical method.

本文对近破波作用下防波堤的动力响应进行了研究，针对防波堤的四种运动情况，建立了沉箱式防波堤的动力分析模型和数值模拟方法，并设计了一个模型实验，通过实验对所提出的理论模型和数值模拟方法进行了检验。

However, the hydrodynamic characteristics , the mechanism of the interaction between waterwaves and semi-circular breakwaters have not been studied in details, as well as thenumerical model.

半圆型防波堤是一种具有很好的推广应用前景的新型防波堤结构，自从在天津港工程和长江口深水航道治理工程中得到应用后，我国已经在设计和施工中积累了丰富的经验，但对这种新型防波堤的水动力学特性、波浪与半圆型防波堤相互作用的力学机制以及相应的数值模拟方法还缺乏系统的研究。

By the time of its fall, most of the prisoners were writers who had written against the corruptions of the government.

到它被攻陷的时候，里面多数的犯人是写了反对政府贪污文章的作家。

The most obvious variation to ovum morphological character was that the color was changed from light green to sepiaceous in embryonic development, and all the ovums were almost hatched after 96h.

在胚胎发育过程中卵的形态特征最明显的变化是颜色从淡绿到深褐色，卵在发育96h后卵基本全部孵化。