潜艇尾流场中螺旋桨非自由声场的预报

Non-free filed noise prediction for submarine propeller in wake filed

为在频域内分析潜艇艇体声散射效应对尾流场中螺旋桨声场的影响,以小比例潜艇和大侧斜螺旋桨为对象,首先基于计算流体力学(CFD)方法模拟了“艇+桨”的推进特性,得到了螺旋桨壁面的脉动压力,然后考虑艇体的散射效应,计算分析了螺旋桨的声场特性.结果表明:当以“艇+桨”系统为对象真实模拟螺旋桨的工作条件时,由于潜艇尾部十字舵的存在,因此螺旋桨前方不均匀轴向进流出现四个低速区,导致轴向测点处单个桨叶自由场噪声在4倍轴频及其谐频处有线谱出现;螺旋桨的散射声场与入射声场存在较大差异,并且艇体散射对径向测点螺旋桨噪声的影响要高于轴向测点.

To analyze the influence of hull sound scattering on noise of propeller working in wake filed of submarine,a small-scaled submarine and highly-skewed propeller was taken as the object.First,the propulsion of“submarine+propeller”system was simulated using computational fluid dynamics(CFD),and the fluctuating pressure of propeller was obtained.Then,the propeller noise was calculated and analyzed considering the sound scattering.Results show that when the“submarine+propeller”system is taken as the object to simulate working condition of propeller,there are four low velocity regions in the axial nonuniform inflow in front of propeller as the result of stern cross rudders,line spectrums in free filed noise of single blade noise at the fourth order of axis passing frequency and its harmonics in axial.There are notable differences between the scattered sound field and incident sound field of propeller,and the influence of sound scattering of submarine hull on propeller sound field is greater in radial than that in axial.