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毕业论文网 > 毕业论文 > 海洋工程类 > 船舶与海洋工程 > 正文

大型拖网渔船耐波性和随浪稳性评估毕业论文

 2021-04-14 09:04  

摘 要

对于一个海岸线绵长的国家来说,渔业资源一定是非常丰富的,但由于近年来无节制地渔业捕捞,导致我国近海渔业资源匮乏,开发新渔场、发展远洋渔业成为一个发展重点。想要发展远洋渔业,就必须实现渔船大型化和先进化,而我国大型拖网渔船发展落后。而且远洋渔船不同于其他海船,渔船遇到恶劣海况的概率更高,加之近年来渔船倾覆事故频发,所以研究渔船的耐波性和稳性变得十分重要的。

本文通过广泛调研,收集有关本课题的资料,得到一些拖网渔船的船型资料、船型参数范围和船舶主尺度经验公式,从而设计出本论文所需大型拖网渔船的主尺度,进而使用catia建模软件得到母型船。并通过了解当今世界渔场分布和主要渔业资源,确定船舶主要活动区域、航行区域海洋环境,为之后船舶水动力分析提供海浪谱参数。

本文主要对大型拖网渔船的耐波性和随波稳性进行评估,通过水动力分析软件计算规则波中的频率响应函数、通过谱分析技术来评估渔船在不规则实际海域船舶耐波性,计算船舶随浪静止在波浪中的复原力臂曲线来评估随浪稳性,最后通过船型变换得到系列船模,研究不同船型参数对耐波性和稳性的影响。

通过对大型拖网渔船的耐波性预报,知道在顺浪和迎浪航行时垂荡、横摇较小,船舶在航行时应尽量避免斜浪,以免发生较大的横摇。计算不同航速下迎浪航行时的无因次传递函数,得知航速越高,垂荡和纵摇响应越剧烈。比较不同L/B对船舶耐波性影响,知道L/B对迎浪航行时的垂荡和纵摇影响不大,随着L/B的增大船舶横摇增大。

船舶在波浪中航行,当船速等于波速,此时船舶随浪航行,容易发生纯稳性丧失而导致船舶稳性不足倾覆。通过船舶复原力臂曲线可以看出当波高增加时船舶稳性降低。分析不同L/B对船舶随浪稳性的影响,得出随着B/d的增加,稳性增强。

本文研究船舶耐波性时设置360°8个浪向,但其中有三组浪向重复,显得冗余。只对有航速迎浪情况下的耐波性进行了分析,因为船舶有时也会在斜浪情况下航行,所以有航速斜浪情况下船舶耐波性分析也是必要的。在研究船型参数对船舶耐波性和随浪稳性的影响时,只分析了L/B对耐波性的影响和B/d对随波稳性的影响,并没有对其他船型参数的影响进行分析,这也是将来可以进行的研究。

关键词:拖网渔船;耐波性;随波稳性;

Abstract

For a country with a long coastline, the fishery resources must be very abundant. However, due to uncontrolled fisheries in recent years, China’s offshore fisheries resources are scarce, and the development of new fisheries and the development of offshore fishing have become a focus of development. In order to develop offshore fishing, it is necessary to achieve large-scale and advanced fishing vessels, and the development of large-scale trawl vessels in China is backward. In addition, distant-water fishing vessels are different from other sea-going vessels in that they have a higher probability of encountering severe sea conditions. In addition, fishing vessel overturn accidents have occurred frequently in recent years. Therefore, it is very important to study the wave-resistance and stability of fishing vessels.

Through extensive investigations and researches, this article collects information on the subject and obtains ship type data, range of ship parameters, and ship's main scale empirical formulas of some trawler vessels, so as to design the main scale of the large-scale trawler required for this paper, and then use the catia modeling software. Get a mother ship. Through understanding the distribution of fisheries in the world and the major fishery resources, the main active area of the ship and the marine environment of the navigation area are determined, and wave spectrum parameters are provided for the ship's hydrodynamic analysis.

This paper mainly evaluates the wave-resistance and stability of waves of large-scale trawler, calculates the frequency response function in regular waves through hydrodynamic analysis software, and uses spectrum analysis technology to evaluate the wave-resistance of vessels in irregular real seas. The waves are still in the waves of the resilience arm curve to evaluate the stability of the waves, and finally the series of ship models are obtained through the ship type transformation to study the influence of different ship parameters on the wave resistance and stability.

Through the prediction of the wave resistance of large trawlers, it is known that when the waves are sailing and heading for waves, the heave and the roll are small. When the ship is sailing, it should avoid oblique waves as much as possible to avoid a large roll. Calculate the non-dimensional transfer function for sea wave navigation at different speeds, and know that the higher the speed, the heavier the hesitation and pitching response. Comparing the effects of different L/B on the wave resistance of the ship, it is known that L/B has little effect on the heave and pitching when the wave is sailing, and the ship's roll increases as the L/B increases.

The ship sails in the waves. When the speed of the ship is equal to the speed of waves, the ship will follow the waves at this time, and the loss of pure stability will easily occur, resulting in the lack of stability of the ship. It can be seen from the curve of the return arm of the ship that the stability of the ship decreases when the wave height increases. Analyzing the effect of different L/B on the stability of ships with waves, it is concluded that the stability increases with the increase of B/d.

n this paper, when the ship's wave resistance is studied, there are 360° and 8 wave directions, but there are three groups of wave repetitions that appear to be redundant. The analysis of wave-resistance in the presence of speed and head-on is only carried out. Because ships sometimes travel under sloping conditions, it is also necessary to analyze the ship's wave resistance under speed and sloping conditions. When studying the influence of ship parameters on ship's wave resistance and wave stability, only the effect of L/B on the wave resistance and the influence of B/d on the stability of the follow-up wave were analyzed, and the influence of other ship type parameters was not analyzed. This is also a study that can be conducted in the future.

Key Words:trawler;sea keeping;stability;

目 录

绪论 1

1.1 研究背景及目的 1

1.2 拖网渔船概况 2

1.2.1 拖网渔船的简介 2

1.2.2 拖网渔船发展现状 3

1.2.3 拖网渔船的特点 4

1.3 世界渔场简介 5

1.4 渔船耐波性 6

1.4.1 船模实验 6

1.4.2 实船测试 7

1.4.3 理论数值计算方法 7

1.5 第二代完整稳性 8

1.5.1 船舶完整稳性发展历史 8

1.5.2 纯稳性丧失 8

第2章 大型拖网渔船耐波性计算 11

2.1 大型拖网渔船模型建立 11

2.1.1 主尺度选择 11

2.1.2 软件建模 12

2.2 规则波中耐波性计算 15

2.2.1 软件介绍及计算 15

2.2.2 结果分析 17

2.3 不规则波中耐波性预报 25

2.3.1 耐波性预报原理 25

2.3.2 计算与分析 26

2.3.3 特定海况下不规则波耐波性预报 29

第3章 大型拖网渔船随浪稳性评估 31

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