﻿ 双尾鳍船舶纵倾节能及其尺度效应的数值研究
 舰船科学技术  2024, Vol. 46 Issue (3): 56-61    DOI: 10.3404/j.issn.1672-7649.2024.03.010 PDF

1. 高性能船舶技术教育部重点实验室（武汉理工大学），湖北 武汉 430063;
2. 武汉理工大学 船海与能源动力工程学院，湖北 武汉 430063;
3. 中国舰船研究设计中心，湖北 武汉 430064

Numerical research on trim energy saving and its scale effects of a twin-skeg ship
ZHANG Zheng-yang1, LI Zi-ru1,2, WAN Peng-cheng3, QIN Jiang-tao1,2
1. Key Laboratory of High Performance Ship Technology (Wuhan University of Technology), Ministry of Education, Wuhan 430063, China;
2. School of Naval Architecture, Ocean and Energy Power Engineering, Wuhan University of Technology , Wuhan 430063, China;
3. China Ship Development and Design Center , Wuhan 430064, China
Abstract: Trim energy saving is an efficient and accessible means of saving energy in ships ,for the application of trim energy saving, this paper is based on the numerical simulation method of RANS solution to simulate the flow field of twin skeg inland ships under different scale and trim angle conditions. The paper has discussed the influence of the trim angle on the resistance and its components; analyzed the reasons for the variation of the resistance with the trim angle and discussed the scale effect related to the trim energy saving. The results show that for the twin skeg ship discussed in this paper, when sailing at the design speed, the resistance is the lowest when the trim angle is about 1.5°, and there is an obvious scale effect for the ship's trim energy saving.
Key words: twin-skeg     trim optimization     CFD     overset Mesh     scale effect
0 引　言

1 数值方法与验证

1.1 数值模拟方法

 $\frac{\partial u_{i}}{\partial t}+u_{j} \frac{\partial u_{i}}{\partial x_{j}}=F_{i}-\frac{1}{\rho} \frac{\partial p}{\partial x_{i}}+W^{2} u_{i}-\frac{\partial\left(u_{i}^{\prime} u_{f}^{\prime}\right)}{\partial x} 。$

1.2 数值方法的验证

 图 1 典型剖面网格分布示意图 Fig. 1 Typical profile grid distribution diagram

 图 2 验证船阻力数值结果与试验结果对比 Fig. 2 Comparison of numerical results and experimental results for verification ship resistance
1.3 数值模拟不确定度分析

2 双尾鳍内河船纵倾节能数值研究

2.1 数值对象与工况

 图 3 双尾鳍内河船几何模型 Fig. 3 Geometric model of twin skeg inland ship

2.2 数值模拟结果

 图 4 船模纵倾角随重心纵向位置XG的变化曲线 Fig. 4 Variation curve of trim angle of ship model with longitudinal position of center of gravity XG

 图 5 阻力系数随重心纵向位置的变化曲线 Fig. 5 Variation curve of the resistance coefficient with the longitudinal position of the center of gravity

 图 6 湿表面积随重心纵向位置的变化曲线 Fig. 6 Variation curve of wet surface area with the longitudinal position of the center of gravity

 图 7 不同纵倾条件下自由液面兴波波形比较图 Fig. 7 Comparison of free surface wave under different trim conditions

 图 8 y/B =0.48位置处兴波波形纵切剖面图 Fig. 8 Longitudinal section of the free surface wave at y/B = 0.48

3个重心纵向位置下的船首极限流线如图9所示。可知，3种纵倾状态下的船首极限流线分布差别较小。

 图 9 船首极限流线分布图 Fig. 9 Limit flow line distribution diagram of bow

3个重心纵向位置下的船尾极限流线如图10所示。可知，极限流线在船体平行中体与双尾鳍过渡位置发生了分离现象，并产生了明显的舭涡，这是由船体在此位置处曲率变化较大引起。随着船舶纵倾由尾倾向首倾变化，舭涡产生的位置也向船尾方向移动，且云图显示舭涡的形成也有一定的减弱的趋势。

 图 10 船尾极限流线分布图 Fig. 10 Limit flow line distribution diagram of stern

 图 11 不同重心纵向位置下船尾压力系数分布图 Fig. 11 Distribution of stern pressure coefficient under different longitudinal position of center of gravity
 ${C_p} = \frac{{p - \rho gh}}{{\frac{1}{2}\rho {v^2}}} 。$

3 双尾鳍内河船纵倾节能的尺度效应

 图 12 不同缩尺比阻力系数对比图 Fig. 12 Comparison of resistance coefficients for different scale

 $\delta = ({C_{\max }} - {C_{\min }})/{C_{\max }}\% 。$

4 结　语

1）本文所讨论的双尾鳍内河船型最佳纵倾角度为首倾1.5°左右；总阻力与剩余阻力随船舶重心纵向位置的前移（船舶由尾倾向首倾变化）而减小，摩擦阻力变化较小。

2）船舶纵倾节能存在明显的尺度效应，在总阻力系数与剩余阻力系数的变化上体现的较为明显。

3）重心纵向位置变化导致船舶纵倾角的改变引起船体周围流场的变化，不同纵倾角下船体表面压力分布也有明显不同，是影响船模阻力变化的重要因素。

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