多类振动噪声源下舰船水下噪声的耦合声场计算方法

Coupled Sound Field Calculating Method for Ship Underwater Noise Excited by Multiple Categories of Vibration and Sound Sources

针对具有DTMB 5415船型的某护卫舰,提出水动力、机械和螺旋桨等3类典型振动噪声源共同作用下舰船低中频水下噪声的耦合声场计算方法.基于URANS方法采用SST k-ω湍流模型,数值模拟了该舰在某航速下的非定常流场,并将其作为该舰的水动力噪声源;以某型螺旋桨的脉动压力与实测噪声数据作为机械振动源和螺旋桨噪声源.建立了该舰结构有限元-流体声学间接边界元(FEM-IBEM)声振耦合计算模型,以船体结构前40 000阶干模态作为声振耦合求解声学响应的模态基,计算了该舰在上述3类噪声源共同作用下0～500 Hz水下辐射声功率级,分析了各类噪声源辐射噪声的指向特性和频谱特性.比较了工程中常用的各噪声源辐射声级直接线性叠加方法与耦合声场计算方法的差异.研究表明,耦合声场计算方法的计算效率和精度更高,是多类振动噪声源激励下舰船低中频水下辐射噪声预报的优选数值计算方法.

Aiming at a frigate model based on the DTMB 5415 hull form, a coupled sound field calculating method for ship underwater radiation noise in low-middle frequencies was discussed by considering three typical categories of vibration and sound sources, mechanical, propeller and hydraulic noise. A vibroacoustic coupling FEM-IBEM(the finite element method-indirect boundary element method) model for the frigate was established, and the front 40 000 order modes were calculated as the modal basis for the acoustic response. This study then calculated the acoustic radiated power level in 0-500 Hz and analyzed directional properties and spectral characteristics for every noise component, and it compared the differences between the direct superposition and the coupled sound field calculating methods. The research shows that the physical model of the coupled method is more exact and efficient, and it is a preferred method for ship underwater radiation noise numerical prediction in low-middle frequencies excited by multiple categories of vibration and sound sources.