螺旋桨流激噪声与泄涡频率关系分析

A Study on the Relation Between Flow-Induced Noise and Vortex Release Frequency of Propellers

针对流激振动会引起非线性的流激噪声,严重时会引起“唱音”现象,进而对船舶的正常运行造成巨大影响的问题,基于自定义函数对螺旋桨桨叶随边处的压力进行分析,得到泄涡频率。采用声学边界元方法对泄涡频率与螺旋桨固有频率接近和远离时的螺旋桨噪声进行预报和对比。分析结果表明:泄涡频率附近有多条线谱,形成了一个泄涡频率区域,而不同弹性模量的螺旋桨对应着不同的固有频率;当某阶固有频率与该泄涡频率区域接近时,螺旋桨产生的噪声要比远离该区域时的噪声高出约20dB。

Flow-induced vibration can cause non-linear flow-induced noise and leads to the phenomenon of“singing”in case it occurs seriously,which will have a great impact on the operation of ships.In this paper,the pressure of propeller blade along the edge is analyzed based on the user-defined function to obtain the vortex release frequency.The acoustic boundary element method is used to predict and compare the propeller noise that occurred when the vortex release frequency is close to or far from the propeller natural frequency.The results show that there are many lines near the vortex release frequency,which form a region of vortex release frequency,and the propellers with different elastic modulus are corresponding to different natural frequencies.When the natural frequencies of a certain order are close to the region,the noise generated by the propeller is about 20 dB higher than that generated far away.