基于NURBS的球艏构型参数优化与分析

NURBS-based parametric optimization and design of bulbous bow

[目的]设计优良的球艏构型能够改变船舶在水中航行时的船艏兴波,对阻力产生影响来改善整个船体的阻力性能,为此需对球艏构型参数进行优化。[方法]基于球艏参数化表达和NURBS理论,对母型球艏构型进行数据点网格生成和定义点反算,根据参数优化需要,利用优化算法对定义点进行优化调整后,给出优化船型球艏,并利用CFD软件进行仿真计算,与母型构型进行阻力和波形对比,将以球艏重心为代表的球艏参数阻力特征直接体现到构型优化结果中。[结果]结果表明,借助于NURBS曲线可有效将球艏参数优化特征体现出来,方法形象直观,可显著提高球艏构型表示和优化的效率。[结论]该方法简化了整个优化过程,并取得预期的减阻效果。

The well-designed bulbous configuration influences making-waves created by ship, which can be utilized to improve the resistance performance of whole ship, thus the configuration parameters should be optimized. In this research, the data-point mesh generation and control-point calculation of parent-bulb configuration were carried out on the basis of the bulb parametric description and B-spline theory. According to the needs of the optimization, control points were improved to produce a preferable bulb. Next, CFD software was utilized to simulate and calculate models to directly compare the resistance and waveform of the parent-ship to embody the parametric resistance characteristics shown by the orthocenter in the optimization results. The results show that, with the help of B-spline to effectively present the parametric optimization characteristic, the method obtains a vivid and visual pattern, and the efficiency of bow configuration description and optimization is clearly improved. The method simplifies processes of optimization, and the expected goal of resistance reducing has been achieved.