Studies on Minimization of Wave Making Resistance Based on Rankine Source Method
Studies on Minimization of Wave Making Resistance Based on Rankine Source Method
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DOI：
10.2534/jjasnaoe1968.1999.9
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Kazuo Suzuki;Nobuomi Iokamori
中科院分区：
文献类型：
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作者：
Kazuo Suzuki;Nobuomi Iokamori
在Dawson提出的原始Rankine源法中，自由面元的布置是基于双模型流动的流线追踪法。然而，在本研究中，它被椭圆型面板布置所取代。为了满足自由面上的辐射条件，在对应面元的计算域中引入上游差分算子。采用这种新型自由面元，可以使实际船体外形得到更精确的计算结果，因为在近场增加自由面元的密度变得非常容易.根据这种改进的Rankine源方法，讨论了以兴波阻力最小为目标的船体外形改进问题，在该方法中，通过非线性规划技术在规定的设计约束下进行优化。在优化过程中，引入权函数来表示改进的船体曲面，将其与初始船体曲面的等距数据相乘，即可生成新的光滑船体曲面。表达该权重函数的设计参数可以根据非线性规划技术从优化过程中确定。本文采用序列二次规划（SQP）作为非线性规划。作为船体形状改进的实例，选择HTC（汉堡测试案例）集装箱船作为待改进的初始船体形状。
In the original Rankine source method suggested by Dawson, free surface panels are arranged by means of the stream line tracing method based on the double model flow. In the present, study, however, it is replaced by an elliptical type panel arrangement. In order to satisfy the radiation condition on the free surface, the upstream difference operators are introduced in computational domain corresponding to those panels. By employment of this new type free surface panels, more accurate results can be obtained for a practical hull form, because it becomes very easy to increase the density of panels in near field of the ship.According to this improved Rankine source method, a hull form improvement problem to minimize the wave making resistance is discussed, in which the optimization is carried out under the prescribed design constraints by means of the nonlinear programming technique. In the optimization process, a weight function is introduced to represent an improved hull surface, which can generate a new smooth hull surface by multiplying it to the offset data of the initial hull surface. Design parameters expressing this weight function can be determined from the optimization process based on the nonlinear programming technique. In this paper, SQP (Sequential Quadratic Programming) is employed as the nonlinear programming. As an example of the hull form improvement, the HTC (Hamburg Test Case) container ship is selected as the initial hull form to be improved.