ABSTRACT

This paper is aimed to numerically investigate the hydrodynamic and hydro-acoustic behaviours of rotating underwater propeller operating in off-design flow conditions. The performance of the propeller is subjected to significant alteration, as it experiences flow, coming at an angle. For this purpose, numerical simulation is performed for the INSEAN Propeller E779A. Turbulence model based on the two-equation Reynolds Averaged Navier Stokes (RANS) turbulence model, i.e. k–ω SST (Shear Stress Transport) method is implied to assess hydrodynamic performance, while hydro-acoustic assessment in near field is calculated by coupling RANS with the Ffowcs Williams Hawking (FW-H) equation. Validation is performed by comparing the numerically computed results from the current study with the available experimental data in straight flow conditions and then the off-design conditions are modelled by using the combinations of three advance ratios with four different flow angles. As a result, distinct differences among the hydrodynamic and hydro-acoustic features are analysed. The hydrodynamic coefficients are compared, and their change is analysed in detail. For the hydro-acoustic analysis, sound pressure level, attenuation frequency and directivity analysis are conducted and based on these factors the effect of the off-design condition on the aquatic life is discussed, thus showing the strong influence of the off-design condition on the hydro-acoustics of the underwater water propeller.

摘要

本文旨在对非设计流动条件下旋转水下螺旋桨的水动力和水声行为进行数值研究。螺旋桨的性能会发生重大变化，因为它会经历流动，以一定角度出现。为此，对 INSEAN Propeller E779A 进行了数值模拟。基于二方程雷诺平均纳维斯托克斯（RANS）湍流模型的湍流模型，即k – ωSST（剪切应力传递）方法用于评估水动力性能，而近场的水声评估是通过将 RANS 与 Ffowcs Williams Hawking (FW-H) 方程耦合来计算的。通过将当前研究的数值计算结果与直流条件下的可用实验数据进行比较来进行验证，然后通过使用三个提前比和四个不同流动角的组合对非设计条件进行建模。因此，分析了水动力和水声特征之间的明显差异。比较了水动力系数，并详细分析了它们的变化。对于水声分析，声压级，