ABSTRACT

Besides the other hydrodynamic phenomena, the ship design process includes also the accurate prediction of the motions in waves. In this paper, a Discrete Fourier Transform (DFT) based method is presented for calculations of ship motion transfer functions (TFs) by using Reynolds Averaged Navier Stokes (RANS) approach. The DTMB 5512 hull form is selected for the proof of the accuracy of the proposed method at the Froude number of 0.41 and head waves. Instead of sending regular waves separately to the model ship in a virtual towing tank, a wave energy spectrum is defined and the created long-crested irregular wave system is sent to the model ship. With the aid of the DFT technique, irregular vertical ship motions in the time domain are transformed into the frequency domain. With the proposed RANS method, it is reported that CPU time spent for CFD analyses are significantly dropped compared to traditional RANS TFs calculation processes.

摘要

除了其他水动力现象外，船舶设计过程还包括对波浪运动的准确预测。在本文中，提出了一种基于离散傅里叶变换 (DFT) 的方法，用于使用雷诺平均纳维斯托克斯 (RANS) 方法计算船舶运动传递函数 (TF)。选择 DTMB 5512 船体形式是为了证明所提出的方法在 0.41 的弗劳德数和头波下的准确性。不是在虚拟拖曳罐中单独向模型船发送规则波，而是定义波浪能谱并将创建的长波峰不规则波系统发送到模型船。借助 DFT 技术，将时域中的不规则垂直船舶运动转换为频域。使用提出的 RANS 方法，