减阻球首优化设计方法

Optimum approach to bulbous bow design to reduce resistance and improve propulsion

阐述了球首的主要类型、几何特征及其减阻原理． 提出了具有协调性和光顺性的球首变换方法，并在Ｈｏｌｔｒｏｐ 船体阻力预报的基础上，建立了船体阻力和推进效率的加权函数作为球首优化设计的目标函数，在给定的球首几何特征和船形参数的约束下，计算并设计出最佳的球首． 通过对实船的设计结果分析，证明了该方法的先进性和工程实用性．

Bulbous bows are widely used in hull design because of reducing resistance and improving propulsion. The principle, how to decrease the drag after appling some common kind of bulb noses defined with their geometric characteristics, is described at first. And then, in order to transform bow form among different types of bulbous or from non\|bulb bow to bulbous, a new approach is put forward to harmonise and fair form variation. On the basis of Holtrop resistance estimation, the kind of objective function, including the total resistance and the propulsion results and considering the weight factors, is set up to optimise hull bow under the constrained conditions of the essential elements of the hull and bulb. It can be seen that the new approaching is a short\|cut method that is very advanced and practicable by giving the examples of optimum calculation of the real bulbous bow hull form design, so it can be offered to the practical use to design ship lines with lower resistance and higher propulsion in the initial and conceptual ship design.