﻿ 基于重叠网格的两船间水动力干扰计算
 舰船科学技术  2022, Vol. 44 Issue (14): 6-11    DOI: 10.3404/j.issn.1672-7649.2022.14.002 PDF

Numerical simulation of hydrodynamic interference between two vessels based on overlapped grids
YU Xin-yi, WANG Meng-qiao, ZHOU Li-lan
School of Naval Architecture, Ocean and Energy Power Engineering, Wuhan University of Technology, Wuhan 430063, China
Abstract: Activities such as berthing, replenishment, rescue and other activities are becoming more and more common. The disturbance and hydrodynamic performance caused by short distance operation of ships cannot be ignored. In this paper, the method based on Reynolds-averaged equations is used to calculate the hydrodynamic disturbances between two ships in waves, the STAR-CCM+ software was used to simulate the wave generation and wave absorption of regular wave, the motion response characteristics and force characteristics of the two vessels in regular wave under different wave lengths and transverse distances were analyzed. The results show that when the ratio of wavelength to ship length λ/L varies from 0.5 to 1, the lateral force and vertical force suffered by both ships have a sudden change with the wavelength, and when the λ/L is greater than 1.5, the forces of two ships change little.When the wavelength of incident wave is constant, the lateral force and vertical force of the two ships increase first and then decrease with the increasing of the distance between two ships.The results of this paper can be the basis for the safe operation among multiple floating body system in waves.
Key words: numerical tank     overset grid     hydrodynamic characteristics
0 引　言

1 数值方法 1.1 坐标系及结果表达形式

 图 1 两船的随船坐标系 Fig. 1 Coordinate systems of ships
1.2 控制方程与湍流模型

 $\frac{\partial {u}_{i}}{\partial {x}_{i}}=0 \text{，} i=\mathrm{1,2},3 ；$ (1)
 $\mathrm{\rho }\frac{\partial {u}_{i}}{\partial t}+\mathrm{\rho }{u}_{j}\frac{\partial {u}_{i}}{\partial {x}_{j}}=-\frac{\partial p}{\partial {x}_{i}}+\mu \frac{\partial }{\partial {x}_{j}}\left(\frac{\partial {u}_{i}}{\partial {x}_{j}}-\rho \overline{{u}_{i}'{u}_{j}'}\right)。$ (2)

 $\frac{\partial (\rho k)}{\partial t}+\frac{\partial (\rho k{u}_{i})}{\partial {x}_{i}}=\frac{\partial }{\partial {x}_{j}}\left[\left(\mu +\frac{{u}_{t}}{{\sigma }_{k}}\right)\frac{{\partial }_{k}}{\partial {x}_{j}}\right]+{P}_{k}-\rho \varepsilon，$ (3)
 $\begin{split} \frac{\partial (\rho \mathrm{\varepsilon })}{\partial t}+\frac{\partial (\rho \mathrm{\varepsilon }{u}_{i})}{\partial {x}_{i}}=&\frac{\partial }{\partial {x}_{j}}\left[\left(\mu +\frac{{u}_{t}}{{\sigma }_{\mathrm{\varepsilon }}}\right)\frac{{\partial }_{k}}{\partial {x}_{j}}\right]+ \\ &{C}_{\mathrm{\varepsilon }1}{\frac{\mathrm{\varepsilon }}{k}P}_{k}+{C}_{\mathrm{\varepsilon }2}\rho \frac{{\mathrm{\varepsilon }}^{2}}{k}-{R}_{\varepsilon }。\end{split}$ (4)

1.3 重叠网格方法

1.4 自由液面的模拟

2 计算模型及网格划分 2.1 计算模型及边界条件

 图 2 计算域及边界条件 Fig. 2 Computational domain and boundary conditions
2.2 网格划分及无关性验证

 图 3 整个计算域网格 Fig. 3 Grid of whole computational domain

 图 4 重叠网格区域局部网格 Fig. 4 Overset grids
3 数值结果 3.1 数值造波

 图 5 10个周期后的波面图 Fig. 5 Distribution of calculated wave pattern

 图 6 $y=6$ m处波形的时历曲线 Fig. 6 The time history curve of wave pattern at x=6 m

 图 7 规则波10个周期后波形与理论值的对比 Fig. 7 Comparison of calculated wave pattern and theoretical values
3.2 波长的影响

 图 8 试验值与数值计算值的对比 Fig. 8 Comparison of numerical results and experimental data
3.3 横向间距的影响

 图 9 不同间距下两船所受横向力和垂向力的变化规律 Fig. 9 Lateral force and vertical force of two ships with different distances

 图 10 不同间距下两船运动响应的变化规律 Fig. 10 Responses of two ships with different distances

 图 11 一个周期内两船间波面的升高变化 Fig. 11 Distribution of wave heights between two ships
4 结　语

1）在采用基于重叠网格的数值方法计算两船间的水动力特性时，得到了稳定、收敛的计算结果，说明本文采用的方法可行、稳定。

2）计算了在一定横向间距条件下，不同入射波波长对两船横向力和垂向力的影响，发现计算结果与试验结果吻合较好，能够较准确地捕捉到波长变化时两船受力特性的变化规律。

3）在入射波波长一定时，随着两船间距的增加，两船的横向力和垂向力呈现出先增大后减小的趋势，两船的横向力和垂向力分别在 ${S}/{L}=$ 0.35和0.45时达到最大值，说明在此间距条件下两船的相互干扰现象最为明显。同时，随着间距的增加，两船的垂荡运动和横摇运动响应之间变小，并有趋于稳定的趋势，说明当两船间距较大时，两船的相互干扰作用基本消失。

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