﻿ 小水线面双体船声场指向性研究
 舰船科学技术  2020, Vol. 42 Issue (10): 26-29    DOI: 10.3404/j.issn.1672-7649.2020.10.006 PDF

Investigation on the directivity of small waterplane area twin-hull
LI Guang, YAN Bin, JIANG Chen-ban, LIU Zhe
National Key Laboratory on Ship Vibration and Noise, China Ship Scientific Research Center, Wuxi 214082, China
Abstract: Research was carried out on the horizontal directivity, vertical directivity along the width of ship and vertical directivity along the length of ship. The acoustic-structure interaction numerical method was used to analyze the acoustic field coupling between double submersibles of a small waterplane area twin-hull. The regularity of acoustic directivity between left excitation and simultaneous left and right excitation was compared. The research results indicate: because of acoustic field reflection and coupling between double submersibles of a small waterplane area twin-hull, the underwater radiated noise caused by the hull structure has increased. In the low frequency band, the effect of double submersibles on directivity is relatively small because of long acoustic wavelength. As the frequency increases, the number of lobes in the directional graph is gradually increasing, and the directivity of underwater radiated noise is becoming more and more complicated.
Key words: twin-hull     directivity     acoustic-structure interaction
0 引　言

1 声固耦合方法

1.1 流场的模拟

 ${\nabla ^2}p + {k^2}p = 0\text{。}$ (1)

 $\mathop {\lim }\limits_{r \to \infty } r\left( {\frac{{\partial p}}{{\partial r}} + jkp} \right) = 0\text{。}$ (2)

 $p{|_{\text{自由液面}}} = 0\text{。}$ (3)
1.2 声固耦合方程的求解

 $\frac{{\partial p}}{{\partial n}} = - j\rho \omega {v_n}\text{。}$ (4)

 $\begin{split} & \left[ {\begin{array}{*{20}{c}} {{M}_{\rm{e}}^{\rm{s}}}&0\\ {\rho {R}_{\rm{e}}^{\rm{s}}}&{{M}_{\rm{e}}^{\rm{f}}} \end{array}} \right]\left[ {\begin{array}{*{20}{c}} {{{{\ddot u}}_{\rm{e}}}}\\ {{{{\ddot p}}_{\rm{e}}}} \end{array}} \right] + \left[ {\begin{array}{*{20}{c}} {{C}_{\rm{e}}^{\rm{s}}}&0\\ 0&{{C}_{\rm{e}}^{\rm{f}}} \end{array}} \right]\left[ {\begin{array}{*{20}{c}} {{{{\dot u}}_{\rm{e}}}}\\ {{{{\dot p}}_{\rm{e}}}} \end{array}} \right] + \\ & \left[ {\begin{array}{*{20}{c}} {{K}_{\rm{e}}^{\rm{s}}}&{ - {R}_{\rm{e}}^{\rm{f}}}\\ 0&{{K}_{\rm{e}}^{\rm{f}}} \end{array}} \right]\left[ {\begin{array}{*{20}{c}} {{{u}_{\rm{e}}}}\\ {{{p}_{\rm{e}}}} \end{array}} \right] = \left[ {\begin{array}{*{20}{c}} {{F}_{\rm{e}}^{\rm{s}}}\\ 0 \end{array}} \right]\text{。} \end{split}$ (5)

2 计算模型 2.1 数值模型

 图 1 小水线面双体船几何模型与试验模型 Fig. 1 Geometric model and experimental model of SWATH

 图 2 小水线面双体船数值计算模型 Fig. 2 Numerical calculation model of SWATH
2.2 声辐射指向性

 $D\left( \theta \right) = \frac{{{{\left( {{p_a}} \right)}_\theta }}}{{{{\left( {{p_a}} \right)}_{\max }}}}\text{。}$ (6)

 图 3 水平指向性示意图 Fig. 3 Horizontal directivity diagram

 图 4 垂直指向性示意图（船宽方向） Fig. 4 Vertical directivity diagram （along the width of ship）

 图 5 垂直指向性示意图（船长方向） Fig. 5 Vertical directivity diagram （along the length of ship）
3 计算结果分析

 图 6 水下辐射噪声对比 Fig. 6 Comparison of underwater radiated noise

 图 12 沿船长方向的垂直指向性（40 Hz） Fig. 12 Vertical directivity along the length of ship （40 Hz）

 图 7 水平指向性（16 Hz） Fig. 7 Horizontal directivity （16 Hz）

 图 8 水平指向性（40 Hz） Fig. 8 Horizontal directivity （40 Hz）

 图 9 沿船宽方向的垂直指向性（16 Hz） Fig. 9 Vertical directivity along the width of ship （16 Hz）

 图 10 沿船宽方向的垂直指向性（40 Hz） Fig. 10 Vertical directivity along the width of ship （40 Hz）

1）随着频率的提高，指向性图的波瓣数量逐渐增多；

2）同时激励主甲板左右舷时，尽管激励力、船体结构以及流场相对于中纵剖面基本对称，但由于双下潜体之间的声场耦合作用，指向性图相对于船体结构的中纵剖面并不完全对称分布。

 图 11 沿船长方向的垂直指向性（16 Hz） Fig. 11 Vertical directivity along the length of ship （16 Hz）
4 结　语

1）同时激励左右舷主甲板的水下辐射噪声与单独激励左舷主甲板的水下辐射噪声结果差异大于3 dB；

2）随着频率的提高，指向性图的波瓣数量逐渐增多；

3）同时激励主甲板左右舷时，指向性图相对于船体结构的中纵剖面并不完全对称分布；

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