渔船减阻球鼻艏模型优化研究

Optimization study of drag reduction bulbous bow model of fishing boat

为探究球鼻艏变化对渔船水动力性能的影响,在母型船直立艏方案的基础上,以总阻力为优化目标,进行增设球鼻艏设计.首先对渔船进行参数化建模,采用自由变形(FFD)方法对艏部的几何参数进行改造;然后使用拉丁超立方设计方法进行采样,将CFD数值模拟与BP神经网络相结合,建立以高度精确的数值模拟为优化特征的母型船预测模型;最后利用遗传算法对渔船进行目标优化,寻求总阻力优解的设计点.结果表明:基本船型配合增设优解的球鼻艏后,在3种航速情况下,总阻力分别减小0.30%、0.58%、1.02%.

In order to explore the influence of the change of bulbous bow on the hydrodynamic performance of fishing boat, taking the total resistance as the optimization objective, an additional bulbous bow is designed based on the vertical bow scheme of the mother ship. Firstly, the parametric modeling of the fishing boat is carried out, and the geometric parameters of the bow are transformed by using free-form deformation (FFD) method. Then, the Latin hypercube design method is used for sampling, and the method combining CFD numerical simulation and BP neural network is used to establish the mother ship prediction model with highly accurate numerical simulation as the optimization feature. Finally, the genetic algorithm is used to optimize the fishing boat and find the design point of the optimal solution of the total resistance. The results show that the total resistance decreases by 0.30%, 0.58% and 1.02% respectively at three speeds after the basic ship type is combined with the addition of the optimal bulbous bow.