﻿ 月池对船舶水动力导数影响研究
 舰船科学技术  2019, Vol. 41 Issue (3): 42-46 PDF

1. 上海交通大学，海洋工程国家重点实验室，上海 200240;
2. 上海交通大学高新船舶与深海开发装备协同创新中心，上海 200240

Influence of moonpool on hydrodynamic derivatives of ship
LIU Chen-fei1,2, LIU Ya-dong1,2, MENG Yi1,2
1. Shanghai Jiaotong University, State Key Laboratory of Ocean Engineering, Shanghai 200240, China;
2. Shanghai Jiaotong University, Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai 200240, China
Abstract: In order to predict the maneuvering hydrodynamic force of ships with moonpool, this paper applies CFD technology and the overlapping grid technique. Taking the towed system on mother ship as study object, oblique towing, pure sway and pure yaw tests are performed under a series of designated condition. The measured forces and moments are processed and hence the hydrodynamic derivatives of the moonpool open and closed are calculated separately. By means of comparing the simulation results with results calculated by potential flow theory, the rationality and validity of the method are verified. By comparing the hydrodynamic derivatives when the moonpool was closed and opened, most of the hydrodynamic derivatives were found to have increased due to the existence of the moonpool, which provided a reference for predicting the maneuverability of ships with moonpool.
Key words: hydrodynamic derivatives     moonpool     overlap grid     CFD     ship maneuverability
0 引　言

1 基本理论 1.1 控制方程

 $\left\{ \!\!\!\!\begin{array}{l} \dfrac{{\partial \overline {{u_i}} }}{{\partial {x_i}}} = 0\text{，}\\ \dfrac{{\partial \overline {{u_i}} }}{{\partial t}} + \overline {{u_j}} \dfrac{{\partial \overline {{u_i}} }}{{\partial {x_j}}} = - \dfrac{1}{\rho }\dfrac{{\partial \overline {{P_i}} }}{{\partial {x_i}}} + \dfrac{1}{\rho }\dfrac{\partial }{{\partial {x_j}}}\left(\mu \dfrac{{\partial \overline {{u_i}} }}{{\partial {x_j}}} - \rho \overline {{{u'}_i}{{u'}_j}} \right)\text{。} \end{array} \right.$ (1)

1.2 湍流模型

 $\left\{ \!\!\!\!\begin{array}{l} \rho \dfrac{{dk}}{{dt}} = \dfrac{\partial }{{\partial {x_j}}}\left[ {\left( {\mu + \dfrac{{{\mu _t}}}{{{\sigma _k}}}} \right)\dfrac{{\partial k}}{{\partial {x_j}}}} \right] + {G_k} + {G_b} - \rho \varepsilon - {Y_M}\text{，}\\ \rho \dfrac{{d\varepsilon }}{{dt}} \!=\! \dfrac{\partial }{{\partial {x_i}}}\left[ {\left( {\mu \!+\! \dfrac{{{\mu _t}}}{{{\sigma _\varepsilon }}}} \right)\dfrac{{\partial \varepsilon }}{{\partial {x_i}}}} \right]{\rm{ + }}\rho {C_1}S\varepsilon \!-\! \rho {C_2}\dfrac{{{\varepsilon ^2}}}{{k \!+\! \sqrt {v\varepsilon } }} +\\ {C_{1\varepsilon }}\dfrac{\varepsilon }{k}{C_{3\varepsilon }}{G_b}\text{。} \end{array} \right.$ (2)

1.3 重叠网格技术

 图 3 网格划分 Fig. 3 The meshing method
2 计算方法 2.1 船体模型

 图 1 船体模型 Fig. 1 Hull model
2.2 计算域设置

 图 2 计算域与边界条件 Fig. 2 Computational domain and boundary conditions
2.3 网格划分

 图 4 y+值 Fig. 4 The value of y+
3 数值模拟拘束模型试验 3.1 网格收敛性分析

3.2 计算工况和结果 3.2.1 斜航运动

3.2.2 纯横荡运动

 $\left\{ \begin{array}{l} y = a\sin \omega t\text{，}\\ v = \dot y = a\omega \cos \omega t\text{。} \end{array} \right.$ (3)

 $\left\{ \begin{array}{l} \overline Y {\rm{ = (}}m - {Y_{\dot v}})\dot v - {y_v}v\text{，}\\ \overline N = (m{x_G} - {N_{\dot v}})\dot v - {N_v}v\text{。} \end{array} \right.$ (4)
3.2.3 纯首摇运动

 $\left\{ \begin{array}{l} \psi \approx \dfrac{{{u_R}}}{{{u_c}}} = \dfrac{{a\omega }}{{{u_c}}}\cos \omega t = {\psi _0}\cos \omega t\text{，}\\ r = \dot \psi = - \dfrac{{a{\omega ^2}}}{{{u_c}}}\sin \omega t = {r_0}\sin \omega t\text{，} \end{array} \right.$ (5)
 $\left\{ \begin{array}{l} \overline Y {\rm{ = (}}m{x_G} - {Y_{\dot r}}){{\dot r}} - (m{u_G} - {Y_r}){{r}}\text{，}\\ \overline N = ({{\rm{I}}_z} - {N_{\dot r}}){{\dot r}} - (m{x_G}{u_G} - {N_r}){{r}}\text{。} \end{array} \right.$ (6)
3.3 计算数据处理

 图 5 不同漂角下的阻力曲线 Fig. 5 Resistance curves at different drift angles

 图 6 不同漂角下的侧向力曲线 Fig. 6 Lateral force curve at different drift angles

 图 7 不同漂角下的首摇力矩曲线 Fig. 7 Yaw moment curve at different drift angles

 图 8 纯横荡运动船舶受到的侧向力 Fig. 8 Lateral force curve when in pure sway motion

 图 9 纯横荡运动船舶受到的首摇力矩 Fig. 9 Yaw moment curve when in pure sway motion

 图 10 纯首摇运动船舶受到的侧向力 Fig. 10 Lateral force curve when in pure yaw motion

 图 11 纯首摇运动船舶受到的首摇力矩 Fig. 11 Yaw moment curve when in pure yaw motion

 图 12 水动力导数随频率变化曲线 Fig. 12 The change of hydrodynamic derivatives along with frequency
3.4 计算结果分析

 图 13 开口内部流场 Fig. 13 Flow field inside the moon pool

 图 14 开口表面压力分布 Fig. 14 Pressure distribution of the surface of moon pool

4 结　语

 [1] ITTC. Proceedings of 25th ITTC[J], 2008, Volume Ⅰ: 143–203. [2] KIM Y G, KIM S Y, KIM H T, et al. Prediction of the maneuverability of a large container ship with twin propellers and twin rudders[J]. Journal of Marine Science & Technology, 2007, 12(3): 130-138. [3] 蔡创, 蔡新永, 赵传波, 等. 船舶浅水操纵性能的数值仿真[J]. 重庆大学学报, 2012(8): 116-121. [4] OHMORI T. Finite-volume simulation of flows about a ship in maneuvering motion[J]. Journal of Marine Science & Technology, 1998, 3(2): 82-93. [5] SIMONSEN C D, OTZEN J F, KLIMT C, et al. Maneuvering predictions in the early design phase using CFD generated PMM data[J]. [6] 张赫, 庞永杰, 李晔. 基于FLUENT软件模拟平面运动机构试验[J]. 系统仿真学报, 2010(3): 566-569. [7] TURNOCK S R, PHILLIPS A B, FURLONG M. Urans simulations of static drift and dynamic manoeuvres of the KVLCC2 tanker[C]//SIMMAN 2008: workshop on verification and validation of ship manoeuvring Simulation Methods, 2008. [8] [9] 杨勇. 非定常操纵运动船体水动力数值计算[D]. 上海: 上海交通大学, 2011. [10] 邓锐, 黄德波, 于雷, 等. 影响双体船阻力计算的流场CFD因素探讨[J]. 哈尔滨工程大学学报, 2011(2): 141-147. DOI:10.3969/j.issn.1006-7043.2011.02.002 [11] 沈海龙, 苏玉民. 肥大型船伴流场数值模拟的网格划分方法研究[J]. 哈尔滨工程大学学报, 2008(11): 1190-1198. DOI:10.3969/j.issn.1006-7043.2008.11.010 [12] 邢磊. 三体船水动力导数及操纵性能预报研究[D]. 哈尔滨: 哈尔滨工程大学, 2012.