船体艏部水动力性能优化

Hydrodynamic Performance Optimization of Ship Hull’s Forebody

  • 摘要: 提出一种以势流兴波阻力理论Rankine源方法为基础,结合SHIPFLOW 软件为计算工具.利用CAD—CFD集成平台FRIENDSHIP—FrameWork软件进行变形优化.研究船舶的最小兴波阻力型线优化设计的方法.并考察了兴波优化得到的船型总阻力变化情况 在型线优化过程中.以兴波阻力系数为目标函数.排水量变化范围为约束条件.在Wiglev船体前端增加一个利用Feature建模技术参数化生成的球艏并调整艏部型线使得船体表面光顺。选取球鼻艏形状的各项参数作为基本设计变量.利用DOE方法对船艏进行优化.获得了设计航速下兴波阻力较小的船型.验证了所提方法进行船艏型线优化的有效性 相应的考察变形及优化前后总阻力变化情况表明:在高傅汝德数情况下增加球艏所带来的粘性阻力的增加小于兴波阻力的减小量,总阻力得到了改善,优化后得到的球艏能在进一步减小兴波的同时减小总阻力。此外,还运用所提方法对3100TEU船型的船艏,利用Delta Shift方法进行变形,在设计航速下,将变形的参数作为设计变量,利用DOE方法进行优化设计。结果显示:在排水量限制范围内当球鼻艏向上向前伸展一定长度时可以降低兴波阻力 与此同时.由于优化前后船体湿表面积变化很小.粘性阻力的变化并不明显.兴波的减小则使得总阻力得到了改善

     

    Abstract: Based on Rankine Source Method,the paper introduced SHIPFLOW as computing tool,and also combined FRIENDSHIP-Framework which used as integration platform of CAD-CFD to study the minimum wave resistance hull body design.And total resistance was tested.W e chose Wigley hull as the study object and calculated the wave resistances under different Fr conditions.The results were in good agreement with the experiment data.During the optimization process,we chose a new Wigley hull with a bulbous bow generated by the Feature function of FRIENDSHIP-Framework as original hull type,wave resistance as the objective function,displacement as the constraint condition,parameters controlling the shape of the bulbous bow as the basic design variable,and took Design of Experiment(DOE)method as the optimization method.The numerical optimization result gave a low wave resistance ship hull at the design speed.which indicated that the method is effective.The result of total resistance shows that the new type of Wigley hull added a bulb has lower result than the original one,and the optimized type of Wigley hul1 gets the total resistance reduced further due to the reduction of the wave resistance. 3 100TEU was optimized by the same method at its design speed while Delta Shift method was applied to get the transformation.The results show that with the limitation of ship S displacement,the bulbous bow with a forward and upward extending would reduce the wave resistance.Meanwhile,the wetted surface which makes a great deal in the viscous resistance changes little.which means that the viscous resistance does not change significantly,thus the reduction of the wave resistance basically get the total resistance reduced.

     

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