船后喷水推进器水下辐射噪声源脉动流场的数值计算

为避免尺度效应对噪声性能的影响,文章研究探索了在实尺度条件下装船后喷水推进器噪声声源的数值计算方法。首先,基于分离涡模型对国外某喷水推进泵内部非定常流场进行了数值模拟,将计算得到的不同转速下泵的功率值与厂商提供数据进行对比,最大误差在2.0%以内,验证了数值计算方法的准确性和有效性。其次,完成了实尺度条件下某"船体+喷水推进泵+进水流道"系统带自由液面的非定常流场的数值计算。提取了实船条件下喷水推进器流道进口处的不均匀速度场,将其加载到单个喷水推进器数值计算模型的进口边界。进而,采用分离涡模型对该船后"喷水推进泵+进水流道"内部非定常流场脉动压力进行数值计算,分析了各个特征截面压力脉动的频域特性,为下一步准确计算喷水推进器噪声提供了有效的脉动流场信息。

Calculating investigation on pulsing flow for underwater radiated noise of the waterjet

An approach to calculate flow acoustic source of waterjet installed after hull was investigated, which can removes the scale effect and take into account the interaction between the waterjet and the hull. In order to validate the numerical model, the unsteady performance of a waterjet pump was calculated with DES (detached eddy simulation) method and hexagonal structure mesh, and the maximum error between the CFD results of the pump power at different pump rotating speed and the manufacturer's data was 2.0%, which indicated that the numerical method was creditable. The full scale 'waterjet + hull' numerical mod-el was established to study the interaction between the waterjet and the hull, and the non-uniform inlet flow of the waterjet after hull was imposed at the inlet of the single waterjet numerical model with DES method to calculate the pressure fluctuations in the waterjet and take into account the interaction between the wa-terjet and the hull. This paper gives a simple and effective method to calculate the unsteady flow in the wa-terjet after hull.