船模水动力噪声及孔腔激励载荷试验与计算对比分析

Comparative analysis of ship model hydrodynamic noise and hole cavity excitation load tests and calculation

开展某远洋客船光体船模水下噪声测试及带孔腔船模的水动力激励载荷测试,并进行孔腔处稳态和瞬态流场计算,孔腔处脉动压力频谱计算曲线与试验曲线吻合较好。孔腔脉动压力线谱频率测试值与经验公式频率计算值对比良好,说明该公式在一定情况下适用于船体条形格栅孔腔线谱频率的预估。采用统计能量法分析法计算光体船模中高频流激噪声,将流体激励以频率-波数功率谱的形式施加,可大大减少流场计算工作量,适合于工程快速预估。在工程一般范围内,阻尼损耗因子取值可导致噪声结果相差5.5 dB,说明阻尼损耗因子的取值会较大影响计算结果,有必要形成材料损耗因子随频率变化的数据库,为船舶噪声快速计算提供支撑。

Here,underwater noise testing was conducted for a certain ocean-going passenger ship’s bare vessel model and hydrodynamic excitation load testing was conducted for a ship model with a perforated cavity,and steady-state and transient flow field calculations at cavity were performed.It was shown that calculation curve of pulsating pressure spectrum at cavity agrees well with test curve;frequency testing values of pulsating pressure line spectrum at cavity and frequency calculation values obtained using empirical formulas are in consistent;thus,this empirical formula is suitable for estimating spectral frequencies of grid cavity line spectrum of hull under certain conditions.The statistical energy analysis(SEA)method was used to calculate medium and high-frequency flow-induced noise of a bare vessel model,and fluid excitation was exerted in the form of frequency-wavenumber power spectrum to greatly reduce flow field calculation amount and be suitable for rapid engineering estimation.Within the general scope of engineering,damping loss factor values could lead to a difference of 5.5 dB in noise results,so damping loss factor values could more largely affect calculation results.It was necessary to form a database of material loss factor changes with variation of frequency to provide a support for rapid calculation of ship noise.