基于非定常RANS法的船型SBD设计和实船航行优化方法研究

Due to the complexity of the unsteady RANS method and the strongly nonlinear of ship motions in waves, the hull form lines optimization and navigation performance optimization have become a big challenge to deal with. This project focuses on the issues of the hull geometric reconstruction technique based on the Free-Form Deformation (FFD) approach, the solve equations of ship motion responses based on the dynamic structured overset mesh, the hybrid genetic algorithm, the hull form design based on the new pseudo-steady deformation method, navigation performance optimization for full-scale model. For the purpose of illustration, the simulation based design (SBD) optimization frameworks and the navigation performance optimization frameworks have been built using the unsteady RANS method. Firstly, considering the rapidity, seakeeping and maneuverability of a ship, the optimization frameworks have been applied to the optimization of the DTMB5415, the KCS container ship, and the KVLCC1 tanker, respectively. The unsteady RANS method is used to calculate the wave resistance (objective function) at different loading conditions and Fr. The parameters which can change the shape of a ship are taken as the design variables. Under the constraints of the displacement, propulsive and maneuverability, the hull forms have been optimized integrating the optimizer and approximation technique. After the completion of the optimization, the best hull forms have been obtained. Next, in order to obtain minimum total resistance in the real navigation, the hull forms of the three ships have been optimized for total resistance using the trim values as the design variables. Then, the optimal ship type has been tested by experiment. The results show that the present optimization frameworks can be used to optimize the ships for reducing the wave resistance and improving the performance of the ships for seakeeping and maneuverability, and also can provide technical support for the design of green ship.

由于船舶在风浪中运动的强非线性和非定常RANS法的复杂性，使得实船线型优化和航行控制优化研究具有挑战性。本项目重点研究基于自由变形法的船体几何重构技术，基于动态结构重叠网格技术的船舶六自由度运动求解方法，混合遗传算法和新型伪定常变形法的船型优化策略，实船航行优化控制方法，构建基于非定常RANS法的船型SBD设计和实船航行优化设计框架。综合考虑船舶的快速性、耐波性和操纵性，以DTMB5415军舰、KCS集装箱船、KVLCC1油船为研究对象，以非定常RANS法计算多载况、多航速下的波浪阻力为目标函数，以反映船体形状变化的参数为设计变量，以排水量限制为基本约束条件，结合混合遗传算法进行优化计算，获得理论上的优化船型，再以此船型为母型，研究以最小纵倾值为设计变量的航行控制优化，以此来评估该船型在实际航行中的阻力性能，最后通过船模试验验证航行性能最优船型。其研究成果可为“绿色船舶”设计提供技术支持。

在低碳经济条件下，船舶的设计理念和设计思想都发生了巨大变化，寻求综合航行性能最优的船型设计逐渐取代了以静水阻力最小为目标的船型优化。在“绿色船舶”设计和建造的理念下，节能、减排成为未来船型设计的主题。因此，本项目提出了最优超立方设计近似模型的优化策略求解船型优化这类复杂的非线性优化问题，丰富CFD的求解技术，补充最优化理论。建立了基于非定常RANS法的船型SBD设计与综合航行优化设计框架，完善、提升船型优化和“绿色船舶”设计方法。研究了基于几何造型法的船体几何重构技术，该技术能够反映船体几何形状的微小变化对阻力性能的影响；基于CFD基础理论和CFD通用软件Star ccm建立了数值波浪水池，采用重叠网格技术划分计算域，切割体网格划分背景域，成功模拟出DTMB5512标准模型的波浪阻力和运动响应，计算结果和实验值具有很好的一致性；提出了求解船型优化问题高效、实用的最优化设计方法，为了提高算法的搜索能力，对算法进行了改进，主要有：粒子群优化算法、改进粒子群算法I、II、III、BP神经网络和粒子群混合算法等；为了提高优化计算速度，建立最优拉丁超立方设计近似模型来代替物理模型，成功地实现了最小波浪阻力船型设计与优化；基于ISIGH优化平台，将船体几何重构技术、CFD数值模拟技术（Star ccmCFD软件）、最优化方法（粒子群算法、改进粒子群算法、BP神经网络和粒子群混合优化算法）、近似技术进行综合集成，构建基于非定常RANS法的最小波浪阻力船型优化设计框架，分别以数学船型Wigley、KCS集装箱标准船模、DTMB5512滨海战斗舰标准模型为例进行设计优化，获得了性能优良的改良船型，最后，通过水池实验验证了优化船型的实际降阻效果。在国际和国内会议上宣读了相关的研究成果；在国内外高水平学术期刊上发表论文13篇、获得发明专利2项、完成专题实验报告1项、出版学术专著2部、培养博士研究生2名、硕士研究生9名。项目的研究成果可为开发具有自主知识产权的新船型开发提高有意借鉴。