基于CFD和响应面方法的最小阻力船型自动优化

Ship hull automated optimization of minimum resistance via CFD and RSM technique

计算流体动力学CFD方法凭借其较高的计算精度和获取更多流场信息的能力逐渐成为新船型设计重要手段。文章利用iSight多学科优化平台建立了一套船型优化系统,集成了CFD技术、船型变换及自动生成技术和响应面代理模型技术和组合优化算法。编制了船型参数变换和生成系统实现了船型变换和CFD计算程序Shipflow输入数据的自动连接;通过对主要船型参数的控制,实现整个船型优化流程的自动化。采用了进化遗传算法(GA)与二次序列规划法(SQP)相结合的二阶组合优化方法实现了从全局探索再到局部空间寻优的整个流程。同时,将响应面近似模型(RSM)引入到优化进程中,解决了计算精度与优化效率间的矛盾,使得高精度的CFD分析工具融入到船舶优化设计进程中成为可能。最后利用该系统对一条设计船的阻力性能进行了优化。

CFD based Ship hydrodynamic Performance analysis,due to its high accuracy,efficiency and more flow information,has become a decisive factor in the development of new ship forms.In this paper,a hull form optimal system is established by means of iSight Multidisciplinary Optimization platform on which the CFD technology,hull transformation and automatic generation,Response surface metamodel technology and hybrid optimization algorithm are integrated.The hull form transformation and generation program is developed so that hull form transformation is automatically connected with CFD commercial code SHIPFLOW computation.Through controlling the principal dimensions and shape parameters,the entire automatic optimization process is implemented.The Genetic Algorithm-Sequential Quadratic Programming combined second order hybrid optimization method is applied to implement the process from the global optimization to searching local space optimum solution.Meanwhile,the Response Surface Method is introduced to the optimization process,which constitutes a balance between the calculation accuracy and op-timization efficiency,and makes it possible for the CFD method being adopted in the process of ship hull optimization.Finally,this optimal system is successfully applied in the resistance optimization of an actual ship and better resistance performance is acquired.