﻿ 航行要素对坞舱水深分布及船尾流场特性的影响
 舰船科学技术  2022, Vol. 44 Issue (16): 39-44    DOI: 10.3404/j.issn.1672-7649.2022.16.008 PDF

1. 中国船舶及海洋工程设计研究院，上海 200011;
2. 喷水推进技术重点实验室，上海 201100

Research on influence of carrier navigation parameters on well deck water depth distribution and wake flow
WANG Nai-han1, ZHAO Ji1, ZHANG Xiang-rui1, FENG Pei-yuan1,2
1. Marine Design and Research Institute of China, Shanghai 200011, China;
2. Science and Technology Laboratory of Water-jet Propulsion, Shanghai 201100, China
Abstract: As a relatively special type ,the ship with well deck directly connects the external water area for the rapid access of carried boats and vehicles, through sinking and floating operation. Carrier with a certain forward speed will influence the depth distribution in well deck and its wake flow. It is necessary to evaluate the well deck water depth in advance to avoid problems such as floating equipment shelf and bumping. By adopting the geometry model that contain well deck and gangplank, employing body-force model to considering propeller effects and proposing strategy for controlling propeller revolution, a numerical model for flow around ship with well dock is contributed. Through analyzing the water depth in well deck when changing ship advancing speed and gangplank attack angle, the water distribution mechanism in semi-open flow domain can be obtained. The results shows that, The water level in well deck is lower than that of avenge free surface when stable. The higher the ship speed, the lower the water level in the well deck. The larger the angle of gangplank, the worse the stability of water. This study can provide reference for the design of ship with well dock, and provide technical means for safety assessment of floating equipment inward and out dock.
Key words: ship with well deck     semi-open flow domain     gangplank     body-force model     wake flow
0 引　言

1 数值计算方法简介

1.1 控制方程

 $\dfrac{\partial \rho }{\partial t}+\nabla \cdot \left(\rho \mathit{u}\right)=0 ,$ (1)
 $\frac{\partial \mathit{u}}{\partial t}+\mathit{u}\cdot \nabla \mathit{u}=-\frac{1}{\rho }\nabla p+\nabla \cdot \left({\nu }_{eff}\left(\nabla \mathit{u}+{\left(\nabla \mathit{u}\right)}^{{\rm{T}}}\right)\right)+{\mathit{f}}_{\sigma }+{\mathit{f}}_{b} 。$ (2)

 $\frac{\partial \alpha }{\partial t}+\nabla \cdot \left(\alpha \mathit{u}\right)+\nabla \cdot \left[\left(1-\alpha \right)\alpha {\mathit{u}}_{r}\right]=0，$ (3)

 ${\mathit{f}}_{bx}=\frac{105}{8}\times \frac{T}{{\text{π}} {t}_{b}\left(3{R}_{H}+4{R}_{p}\right)\left({R}_{p}-{R}_{H}\right)}\times {r}^{*}\sqrt{1-{r}^{*}} ，$ (4)
 ${\mathit{f}}_{b\theta }=\frac{105}{8}\times \frac{Q}{{\text{π}} {t}_{b}\left(3{R}_{H}+4{R}_{p}\right)\left({R}_{p}-{R}_{H}\right)}\times \frac{{r}^{*}\sqrt{1-{r}^{*}}}{{r}^{*}\left({R}_{p}-{R}_{H}\right)+{R}_{H}}，$ (5)
 ${r}^{*}=\frac{r-{R}_{H}}{{R}_{p}-{R}_{H}}。$ (6)

1.2 转速控制

 ${R}_{T}=NT。$ (7)

 $n=60\sqrt{\frac{{R}_{T}}{\rho N{D}^{4}{K}_{T}}}。$ (8)

2 坞舱内水体运动仿真结果分析 2.1 计算模型及网格收敛性分析

 图 1 带坞舱船舶仿真计算域 Fig. 1 Computation domain for ship with well deck

 图 2 计算网格划分 Fig. 2 Mesh of the computational domain

 图 3 自由面监测线波高 Fig. 3 Wave elevation on monitor lines

2.2 舱内水体运动规律研究

 图 4 监测位置示意图 Fig. 4 Schematic diagram of monitor position

 图 5 监测点水体运动时历 Fig. 5 Wave elevation history on monitor points

 图 6 监测线上水体分布 Fig. 6 Wave elevation on monitor lines

 图 7 船尾附近流场速度云图 Fig. 7 Velocity contour around stern

2.3 航速对舱内水体运动影响研究

 图 8 不同航速时舱内水体等值线图 Fig. 8 Velocity contour in well deck at various advancing velocity

 图 9 不同航速波高对比图 Fig. 9 Wave elevation at various advancing velocity

 图 10 不同航速下舱内水深 Fig. 10 Wave depth at various advancing velocity

2.4 尾跳板攻角对舱内水体运动影响研究

 图 11 不同攻角跳板波高对比图 Fig. 11 Wave elevation of longitudinal section at various gangplank attack angel

 图 12 不同攻角下流场特征参数图 Fig. 12 Flow field characteristics at various gangplank attack angel

3 结　语

1）半开敞坞舱内的水体与船几乎相对静止，与外流域对流较小，内外水域交接处会存在较大涡结构。

2）在船舶下放跳板后，坞舱舱内水体会经历较长周期的倾斜与回复运动，坞舱内侧水体运动幅度较大。

3）坞舱内水体稳定后，水位会低于平均自由面。且母船航速越高，舱内水位越低。

4）尾跳板攻角对坞舱内水深影响不大，但会显著地影响坞舱内水体的稳定性。

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