This paper is concerned with the spectral characteristics of leak noise at the source relevant to fluid dynamics for natural gas pipelines. Comparison is made between the flow field characteristics for the buried and above-ground pipelines to demonstrate the differences in aero-acoustics generation mechanism. The fundamental spectral parameters including the sound pressure level (SPL) and power spectral density (PSD), are extracted to characterize the leak noise under different pipeline conditions of operation pressure and leak orifice diameter. Numerical results show that the leak noise of buried pipelines has less energy and are more concentrated at lower frequencies, compared with that of above-ground pipelines. It is demonstrated that leak noise is predominantly governed by the dipole and the quadrupole sources, generated from the gas–solid interaction and turbulent disturbance, respectively. It is shown that the dipole source is attenuated and the quadrupole source is amplified with the leak orifice diameter for buried pipelines whereas both are amplified for above-ground pipelines. Moreover, it is suggested that the feature parameters of fluid dynamics, such as the average dynamic pressure and turbulent kinetic energy, can be used to characterize the leak noise mechanism for natural gas pipelines.

中文翻译：

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天然气管道泄漏噪声特性的理论研究

本文关注与天然气管道流体动力学相关的源泄漏噪声的频谱特性。对埋地管道和地上管道的流场特性进行比较，以证明气动声学产生机制的差异。提取声压级(SPL)和功率谱密度(PSD)等基本谱参数来表征不同管道运行压力和泄漏孔直径条件下的泄漏噪声。数值结果表明，与地上管道相比，埋地管道的泄漏噪声能量较小，且在较低频率处更集中。已经证明泄漏噪声主要由偶极子和四极子源控制，分别由气固相互作用和湍流扰动产生。结果表明，对于埋地管道，偶极源被衰减，四极源被放大，而对于地上管道，两者都被放大。此外，建议使用流体动力学的特征参数，如平均动压和湍动能，来表征天然气管道泄漏噪声的机理。