Abstract Identification of regions on a vibrating structure which radiate energy to the far field is critical in many areas of engineering. Non-negative intensity is a means to visualize contributions of local surface regions to sound power from vibrating structures. Whilst the non-negative intensity has been used for structures under deterministic excitation due to structural forces or harmonic incident acoustic pressure excitation, it has not been considered for analyzing a structure under stochastic excitation. This work analytically formulates non-negative intensity in the wavenumber domain to investigate the surface areas on a vibrating planar structure that are contributing to the radiated sound power in the far field. The non-negative intensity is derived in terms of the cross spectrum density function of the stochastic field and the sensitivity functions of either the acoustic pressure or normal fluid particle velocity. The proposed formulation can be used for both infinite planar structure and finite plate in an infinite baffle. To demonstrate the technique, a simply supported baffled panel excited by a turbulent boundary layer as well as an acoustic diffuse field is considered and those regions contributing to the radiated sound power are identified. It is demonstrated that the non-negative intensity distribution is dependent on the stochastic excitation. It is also found that for a panel under stochastic excitation the more the non-negative intensity distribution is concentrated within the panel surface, the more efficient the panel radiates sound to the far field.

中文翻译：

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随机激励下平面结构的非负强度

摘要 振动结构上向远场辐射能量的区域的识别在许多工程领域至关重要。非负强度是一种可视化局部表面区域对来自振动结构的声功率的贡献的手段。虽然非负强度已用于在结构力或谐波入射声压激励下的确定性激励下的结构，但尚未考虑将其用于分析随机激励下的结构。这项工作分析地制定了波数域中的非负强度，以研究对远场辐射声功率有贡献的振动平面结构上的表面积。非负强度是根据随机场的交叉谱密度函数和声压或正常流体粒子速度的灵敏度函数导出的。所提出的公式可用于无限平面结构和无限挡板中的有限板。为了演示该技术，考虑了由湍流边界层和声学扩散场激发的简单支撑的挡板面板，并确定了对辐射声功率有贡献的那些区域。结果表明，非负强度分布取决于随机激发。还发现对于随机激发下的面板，非负强度分布越集中在面板表面内，