小水线面双体船(SWATH)水动力设计毕业论文
2020-04-12 16:34:57
摘 要
作为一种高性能船,SWATH由于其水线面面积较小,而具有优良的耐波性,能够在较高的海况下平稳地航行。但是,较小的水线面面积也使得SWATH的纵倾复原力矩相应变小。随着速度的增加,作用在船体的MUNK力矩会以速度的平方迅速增加,使得复原力矩不足以抵消纵倾力矩,导致船体出现严重的首倾,失去纵向稳定性。目前解决这个问题的有效方法是在船体两个下潜体的内侧安装稳定鳍。
本文通过广泛阅读SWATH相关文献,对SWATH展开调研并收集国内外现有SWATH实船资料。通过实船资料分析了它们的吨位、航速与尺度变化,简要阐述了现阶段SWATH船型的尺度规律和实船应用情况。通过薄船理论和细长体理论分析SWATH的兴波阻力变化特点 ,并确定SWATH的尺度。然后学习和应用建模软件Solidworks完成SWATH的船型建模,学习maxsurf软件完成其静水力计算。并学习和应用粘性流软件star-ccm 数值模拟光体SWATH船的阻力。结果显示随着傅汝德数的增加,光体SWATH的总阻力不断增大,船体逐渐下沉,在纵向上船体向船艏倾斜,且倾斜程度也随着速度的增加而增大。在Fr=0.4附近船体发生纵向失稳。
为了提高船体的纵向稳定性,接着完成改善纵向运动稳定性的首尾鳍的设计并对增加首尾鳍的SWATH在静水中进行计算分析。结果显示SWATH增加首尾鳍后其总阻力相比于光体船模是增大的。但由于首尾鳍的存在,其纵向倾斜程度明显减小,稳定性得到改善,升沉也有所减小,可以在更高的航速下航行而不会发生纵向失稳现象。这验证了首尾稳定鳍对改善SWATH的纵向稳定性有着良好的效果。对SWATH船型,稳定鳍设计是其水动力设计和船型设计的一个重要部分。
关键词:小水线面双体船;阻力;稳定鳍;纵向稳定性
Abstract
As a high performance ship, SWATH is able to sail smoothly under high sea conditions due to its small waterplane area and excellent seakeeping ability.But small waterplane area of SWATH also makes its trim moment decreases accordingly.With the increase of speed,the MUNK moment acting on the hull will increase with the square of the speed quickly, which makes the restoring moment is not enough to offset the trim moment, lead to a serious bow of the ship hull and lose the longitudinal stability eventually.At present, the effective method to solve this problem is to install stabilizing fins on the inside of the hull.
Through extensive reading of relevant literature,this paper conduct research on SWATH and collect the domestic and foreign existing real ship data of SWATH. Then this paper analyzes thier tonnage, speed and scale changes and briefly expounds the scale law and the real ship application situation of SWATH at this stage through real ship data.Through the thin ship theory and the slender body theory, the wave resistance variation characteristics of SWATH are analyzed, and the scale of SWATH is determined.Then learning and applying the modeling software SolidWorks to complete the SWATH model and learn the Maxsurf software to complete its static hydrostatic calculation.And the viscous flow software star-ccm was used to simulate the resistance of the naked SWATH ship. Calculation results show that with the increase of froude number, the naked SWATH ship’s total resistance is increase,as its hull sink gradually and the hull is tilted to the bow in the longitudinal,and the tilt also increased with the increase of the speed.The hull longitudinal instability occurs near Fr = 0.4.
In order to improve the longitudinal stability of the hull, the design of the fore-and-aft fin to improve the longitudinal motion stability was completed and the analysis was carried out for SWATH with fore-and-aft fin in the static water.The results showed that the total resistance of the SWATH ship with fore-and-aft fin increased compared with the naked hull. However, due to the existence of the fin, the longitudinal inclination of the hull is significantly reduced, the stability is improved, and the heave is also reduced, so that it can sail at a higher speed without the occurrence of longitudinal instability. This verified that the fore-and-aft fin stabilizer had a good effect on improving the longitudinal stability of SWATH. For the SWATH ship, the stabilizing fin design is an important part of its hydrodynamic design and hull design.
Keywords: small waterplane area twin-hull ship, resistance, stabilizing fin, longitudinal stability.
目 录
第1章 绪论 1
1.1 SWATH概况 1
1.1.1 SWATH的结构特点 1
1.1.2 SWATH的优缺点 2
1.1.3 SWATH的用途 2
1.2 国内外发展和研究现状分析 3
1.3 应用前景和发展趋势 11
1.4 目的和意义 12
1.5 研究的基本内容 12
第2章 SWATH兴波阻力预报及尺度选择 14
2.1 薄船理论和细长体理论 14
2.1.1 薄船理论 14
2.1.2 细长体理论 15
2.2 SWATH主要船型参数对兴波阻力的影响 17
2.3 SWATH几何参数的确定 18
第3章 光体SWATH的静水力及阻力计算 21
3.1 maxsurf软件介绍及star-ccm 软件介绍 21
3.1.1 maxsurf软件介绍 21
3.1.2 star-ccm 软件介绍 21
3.2 光体SWATH静水力计算 22
3.3 光体SWATH阻力计算 25
3.3.1 star-ccm 的设置 25
3.3.2 网格独立性研究 26
3.3.3 时间步长适应性研究 30
3.3.4 光体SWATH计算结果分析 31
第4章 带首尾鳍的SWATH阻力计算及分析 35
4.1 首尾鳍的基本原理 35
4.2 首尾鳍的安装位置与尺度确定 36
4.3 首尾鳍对SWATH阻力与航态影响 37
第5章 总结 41
参考文献 42
致谢 44
第1章 绪论
1.1 SWATH概况
海洋面积占据地球表面面积约70%,其中蕴含着丰富的海洋资源,而当前,中国的经济体系已经发展成为高度依赖海洋的外向型经济,对海洋资源,空间的依赖程度迅速增加。中共十八大报告提出,提高海洋资源开发能力,发展海洋经济,保护海洋生态环境,坚决维护国家海洋权益,建设海洋强国。合理开发利用海洋中丰富的资源,成为21世纪科学家和海洋工作者的重要课题。在近几十年来,由于国家海洋的战略需求,我国的船舶行业得到了飞速的发展,而小水线面双体船也作为一种新的高性能船舶得到重视。
1.1.1 SWATH的结构特点
小水线面双体船最近40年新兴起的一种高性能船,又称为SWATH,其概念产生的原因是通过减小船舶的水线面面积来减小船舶航行时的兴波阻力,使波浪对船舶的干扰作用减弱,从而减小波浪扰动力矩,提高船舶的耐波性能[3]。
小水线面双体船由一个水上箱体和两个片体组成,箱体提供全部的使用空间和较大的甲板面积,外形一般为长方形,内部设置舱室,顶部提供宽阔的甲板使用面积,可以根据需要布置各种设备,物品等,而片体提供全部的浮力,片体又可分为支柱部分和下潜体两部分,支柱部分连接箱体和下潜体,并且与水面接触,其横截面呈流线型,下潜体没入水中,装有推进器和推进器传动机构,稳定鳍等装置,并且提供大部分浮力。如下图1.1所示。
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