螺旋桨离散谱噪声计算研究

Study on Discrete Noise lnduced by Marine Propeller

在螺旋桨处于非空泡状态时,离散谱噪声是舰艇辐射噪声的主要成分之一。因而对螺旋桨离散谱噪声进行预报控制至关重要。螺旋桨离散谱噪声计算一般是在螺旋桨非定常力计算和声学计算相结合的基础上得到的。非定常力可以采用面元法或升力面方法计算得到。本文对两种方法进行了比较,结果面元法要优于升力面方法。随后的算例采用面元法计算出螺旋桨非定常力后作为FW-H方程的源项进行了螺旋桨离散谱噪声预报,并通过螺旋桨参数变化可得到离散谱噪声变化规律。

The propeller discrete noise is main part of the vessel noise with non-cavitating propeller.So it is important to predicate the discrete noise.In this paper,propeller discrete noise is predicated with calculating unˉsteady force and acoustics.Both panel method and lifting surface method can be used to calculate the unsteady force.Comparing two methods,the panel method is better.In the example,a propeller is analyzed with panel method,and then the unsteady force is used as the input for Ffowcs Williams-Hawkings formulation to predict the farfield acoustics.Finally,the parameters of propeller effect on discrete noise are concluded.