﻿ 不同舵角的舵翼结构涡量及流噪声特性分析
 舰船科学技术  2018, Vol. 40 Issue (6): 40-44 PDF

1. 海军工程大学 动力工程学院，湖北 武汉 430033;
2. 海军工程大学 船舶振动噪声重点实验室，湖北 武汉 430033;
3. 海军工程大学 科研部，湖北 武汉 430033

Analysis of vorticity and flow noise characteristics of rudder-wing under different rudder angles
QU Duo1,2, ZHANG Zhen-hai3, LOU Jing-jun1,2
1. College of Power Engineering, Naval University of Engineering, Wuhan 430033, China;
2. National Key Laboratory on Ship Vibration and Noise, Naval University of Engineering, Wuhan 430033, China;
3. Office of Research and Development, Naval University of Engineering, Wuhan 430033, China
Abstract: The flow field and sound field of trapezoidal rudder-wing under different rudder angles are numerically predicted by CFD LES theory and Lighthill acoustic analogy theory, and characteristics of vorticity and flow noise are analyzed. Results show that: at the same speed, the vortex is more and more complex and the vorticity and flow noise increases with the increasing of rudder angle; vortex mainly concentrates in stabilizing wing leading edge, trailing edge of rudder-wing and between rudder and stabilizing wing; sound pressure level spectrum band of flow noise is wide and there is no obvious dominant frequency; at the low frequency, sound pressure level is higher, and continues to decline with the increasing of frequency; sound intensity at the front of leading edge and after trailing edge is higher than that at both sides of rudder-wing. This is also consistent with the results of flow field vorticity analysis, which shows that vortex is the root cause of flow noise.
Key words: rudder-wing     vorticity     flow noise     rudder angle     LES     Lighthill acoustic analogy theory
0 引　言

1 流场仿真理论与声学仿真理论 1.1 流场仿真理论

 $\begin{split}& \frac{\partial }{{\partial t}}\left( {\rho {{\bar u}_i}} \right) + \frac{\partial }{{\partial {x_j}}}\left( {\rho {{\bar u}_i}{{\bar u}_j}} \right) =\\ & - \frac{1}{\rho }\frac{{\partial \bar P}}{{\partial {x_i}}} + \frac{\partial }{{\partial {x_j}}}\left( {\nu \frac{{\partial {\sigma _{ij}}}}{{\partial {x_j}}}} \right) - \frac{{\partial {\tau _{ij}}}}{{\partial {x_j}}} \end{split} \text{。}$ (1)

 ${\tau _{ij}} = \frac{1}{3}{\tau _{kk}}{\delta _{ij}} - 2{\mu _t}{\bar S_{ij}}\text{。}$ (2)

1.2 声学仿真理论

Lighthill方程从N-S方程出发导出，方程左边为经典声学的波动方程形式，方程右边是所有流体动力引起的波动项，即声源项。方程描述如下：

 $\frac{{{\partial ^2}\rho '}}{{\partial {t^2}}} - c_0^2{\nabla ^2}\rho ' = \nabla \cdot \nabla {T_{ij}}\text{，}$ (3)

 ${T_{ij}} = \rho {u_i}{u_j} - {\tau _{ij}} + {\delta _{ij}}\left[ {\left( {P - {P_0}} \right) - c_0^2\left( {\rho - {\rho _0}} \right)} \right]$

2 不同舵角的舵翼结构流场预报与涡量场分析

 图 1 舵翼结构几何模型 Fig. 1 Geometry model of rudder

 图 2 流场计算域 Fig. 2 Computational domain of flow field

 图 3 舵翼周围的网格 Fig. 3 Mesh of rudder-wing model

 $Q = 0.5 \times (W \times W - S \times S)\text{，}$ (5)

 $Q = 0.5 \times ({u_{i,j}} \times {u_{i,j}} - {u_{i,j}} \times {u_{j,i}})\text{。}$ (6)

 图 4 舵翼结构在各个舵角下的涡系分布 Fig. 4 Vortex distribution of rudder-wing with each rudder angle
3 不同舵角的舵翼结构声场预报与流噪声特性分析

 图 5 声网格 Fig. 5 Acoustic grid

 图 6 数据映射示意图 Fig. 6 Sketch map of data
 ${p_o} = \frac{{{{{p_1}}/ {{l_1} + {{{p_2}} / {{l_2} + {{{p_3}} / {{l_3} + {{{p_4}} / {{l_4}}}}}}}}}}}{{{1 / {{l_1} + {1 / {{l_2} + {1 / {{l_3} + {1 / {{l_4}}}}}}}}}}}\text{，}$ (7)

 图 7 监控点位置 Fig. 7 Position of monitor points

 图 8 不同舵角下各监控点的声压频谱 Fig. 8 Sound pressure spectrum of each monitor point under different rudder angles

4 结　语

1）来流速度相同时，随着舵角的增大，最大涡量幅值增大，涡系也越来越复杂；而且涡系主要集中在稳定翼的导边、舵翼的尾缘及舵与稳定翼之间。

2）舵翼结构流噪声的声压级频谱频带较宽，无明显的主频率出现；低频时声压级幅值较大，并且随着频率升高而持续下降。

3）在同一流速下，随着舵角的增大，总声压级也在增大，但增大的幅度在减小。

4）舵翼尾缘及稳定翼导边前缘的声场强度比翼型两侧的声场强度大，这也和流场涡量分析结果一致，进而说明了涡流是产生流噪声的根本原因。

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