材料损耗对结构噪声相似性的影响

Influences of Material Loss on the Similarity of Structure Noise

声学相似性是水下结构噪声模型试验的基础。本文研究模型和原型用同一种材料制作时损耗对相似性的影响。以水中有限长圆柱壳体为理论模型 ,用辐射声功率和辐射效率作为表征量导出了相似律。理论分析和对尺寸比1 :2:3的三个壳体的数值计算表明 :若材料损耗与频率无关 ,则损耗不影响相似性 ;若材料损耗是频率的函数 。

Acoustic similarity is the base of scaled model tests of underwater structure noise. This paper investigates influences of material loss on the similarity when scaled model and full scale are made by same material. Similarity rules were derived for a finite cylindrical shell, characterized by radiated sound power and radiation efficiency. Theoretical analysis and numerical calculations for three shells with scale ratio 1:2:3 show that if loss factor does not depend on frequency it has no influence on similarity, and if loss factor depends on frequency it will break similarity.