Abstract

Large eddy simulations and Ffowcs Williams–Hawkings acoustic analogy methods have been adopted to simulate the flow-induced noise for variable cross-section pipelines under variable flow velocity conditions in this paper, and the main influencing factors of flow-induced noise are analyzed numerically, including the flow velocity and variable diameter angle. Results manifested that the flow field distribution, sound source characteristics, and frequency spectrum characteristics of the sound pressure level (SPL) at different flow velocities follow similar trends. The average acoustic source intensity increases gradually with the increase in flow velocity. The maximum of the acoustic source intensity is located near the outlet of the variable diameter angle due to the vortex effect. The flow-induced noise in variable cross-section pipelines is mainly low-frequency noise, and its energy is mainly concentrated below 200 Hz according to the frequency spectrum characteristics. Additionally, the SPL increases with the increase in flow velocity. Compared with v = 1 m/s, the SPL at v = 2 m/s and v = 3 m/s increases by 9.4% and 22.1%, respectively. In addition, there is an approximate linearly increasing relationship between the SPL and the variable diameter angle. The minimum of the SPL appears at φ = 15.2°, and the maximum appears at φ = 25.7° at different flow velocities, which is up to 70.18 dB. Briefly, the flow-induced noise characteristics, including the average acoustic source intensity, the SPL, and the frequency spectra, are revealed in this paper. This provides a theoretical basis for the optimization of variable cross-section piping systems and the investigation of flow-induced noise control techniques.

Highlights

  • Variable cross-section pipelines are widely used in various industries

  • To analyze the effects of different parameters of cross-section pipelines on flow-induced noise, the pressure and velocity distribution, the average cross-sectional pressure, the average acoustic source intensity, and the frequency spectra of the sound pressure level (SPL) generated with different inlet velocities ranging from 1 to 3 m/s are simulated

  • This article mainly focuses on the relationship between the flow velocity and the flow-induced noise

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Summary

Introduction

Variable cross-section pipelines are widely used in various industries. There are many different diameters of pipes connected by variable cross-section pipes. Variable cross-section pipelines are widely used in various industries.. There are many different diameters of pipes connected by variable cross-section pipes. In the variable diameter angle region, the fluid has a large velocity gradient, which generates a large pressure gradient. This leads to the appearance of violent flow-induced noise. The low-induced noise may make a negative impact on the human body. This may cause substantial harm to people’s normal work and life.. It is necessary to conduct an in-depth study on the flow-induced noise of variable cross-section pipelines This may cause substantial harm to people’s normal work and life. On the other hand, the generation of flow-induced noise may damage the stability of industrial equipment, the safety of construction, and the concealment of military fleet, endangering industrial production and military security. it is necessary to conduct an in-depth study on the flow-induced noise of variable cross-section pipelines

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