基于CFD的船舶形状因子随缩尺比及弗劳德数变化规律分析

Analysis of the Variation Law of Ship Shape Factor with Scale Ratio and Froude Number Based on CFD

针对实船阻力预报误差较大的问题,采用CFD软件Fluent分析某大型货船形状因子的变化规律,验证计算方法的准确性,采用叠模计算确定不同缩尺比及弗劳德数时船舶形状因子,结果表明,基于Fluent计算得到的船模阻力与模型试验结果基本吻合,计算方法准确;船舶形状因子(1+k)随缩尺比减小而增加,随弗劳德数增加而增加,主要是由于摩擦阻力占比减小,k值增大。说明实验室在实船阻力换算时对于不同速度均采用同一k值是不合理的,这也是阻力预报存在较大误差的原因之一。

In order to solve the problem of large error in resistance prediction of a large oil tanker,the change law of shape factor of a large oil tanker was studied based on CFD software FLUENT.After verifying the accuracy of the calculation method,the ship shape factor with different scale ratio and Froude number was determined by using the stack model.The results showed that the ship resistance calculated by FLUENT is basically consistent with the model test results,and the calculation method is accurate;the ship shape factor(1+k)increases with the decrease of scale ratio and the increase of Froude number,which is mainly due to the decrease of the proportion of friction resistance and the increase of value.So it is unreasonable to adopt the same value between the model and the real ship at different speeds in the conversion of the real ship resistance,which is also one of the reasons for the large error in resistance prediction.