一种基于体积力螺旋桨模型的自航计算方法

  目的  为了实现对转桨（CRP）推进的高速水下航行体自航因子的数值预报，  方法  建立实尺度航行体阻力、自航及对转桨敞水的RANS模拟方法，进行阻力和敞水计算精度验证，分别采用准定常和非定常方法进行自航模拟，并对自航因子进行分析和比较。  结果  模型尺度的计算与试验比较表明，航行体阻力计算误差小于3%，对转桨推力、扭矩计算误差分别小于2%和4%；实尺度阻力计算结果与基于模型试验的预报结果相差约3%；实尺度自航计算得到的自航因子值均在合理范围；自航因子的准定常与非定常计算结果之差小于2%，说明准定常方法适合于工程应用。  结论  研究方法可为对转桨设计提供较准确的输入数据，可为提高设计精度、缩短设计周期提供技术支撑。

Computational predictions of ship-speed performance

  Objectives  In order to numerically predict the self-propulsion factors of high speed underwater vehicles equipped with Contra-Rotating Propellers (CRP),  Methods  RANS modeling approaches are developed for vehicle resistance, self-propulsion and CRP open-water simulation. In terms of resistance and open-water performance, the modeling accuracy are validated by comparisons with model experiments. Based on quasi-steady and unsteady simulations of a high speed underwater vehicle at full scale, the self-propulsion factors are analyzed and compared.  Results  The comparison of the numerical and experimental results at the model scale indicates that the simulation error margin of vehicle resistance is less than 3%, while those of CRP thrust and torque are less than 2% and 4% respectively. The numerically simulated full-scale resistance is 3% lower than that predicted by the model test data. The self-propulsion factors yielded from full-scale RANS simulations are all reasonable in magnitude. The self-propulsion factors yielded from the quasi-steady and unsteady models differ by less than 2%, indicating that the quasi-steady model is an economical choice for engineering applications.  Conclusions  The present modeling approaches are capable of supplying self-propulsion factors for CRP design with reasonable accuracy, and are expected to enhance design accuracy and work efficiency.