Simulation study on aerodynamic noise characteristics in ventilation ducts with internal baffles

内置挡板的通风管道的气动噪声特性仿真研究

Fundamental Science Research Institute, BYD Auto Industry Co., Ltd., Shenzhen 518118, China

Received: 18 June 2025

Abstract

In this study, a parametric study on aerodynamic noise of a ventilation duct with an internal baffle is conducted based on Lighthill's acoustic analogy method. The variation regularities of far-field noise radiation under different flow velocities and baffle angles are explored. The results show that the aerodynamic noise is mainly dominated by low-frequency components under the working conditions. As the baffle angle and flow velocity increase, the overall noise level rises accordingly, while the noise spectral characteristics remain basically unchanged in most frequency ranges with only amplitude variations. Nevertheless, prominent noise peaks appear at specific frequency points under certain conditions, and such peaks become more pronounced with the decrease of baffle angle. To reveal the noise generation mechanism, a hybrid numerical method is adopted. Specifically, the wall pressure data on the duct inner wall and baffle surfaces are extracted from the computational fluid dynamics (CFD) software STAR-CCM+, which are then converted into dipole sound sources in Simcenter 3D to simulate the noise propagation inside and outside the duct. Internal acoustic field analysis demonstrates that the spectral peaks are mainly induced by Parker modes in the duct, and their frequency locations and amplitudes are closely related to baffle angle and flow velocity. Moreover, higher-order acoustic modes are also observed within the duct. This study clarifies the aerodynamic noise characteristics and generation mechanism of ducts with internal baffles under flow conditions, which provides an important basis for the subsequent noise reduction design.

摘要

基于Lighthill声比拟法对基准通风管道内置挡板这一典型工况的气动噪声进行了参数化研究, 探索了不同流速和不同挡板角度工况下远场噪声辐射的变化规律。结果表明, 此类工况下气动噪声以低频成分为主。随着挡板角度和流速的增加, 噪声水平增大, 在大部分频段范围内其噪声频谱特性未发生明显改变, 仅有幅值偏移; 但在特殊频点处, 某些工况下出现了明显峰值, 且挡板角度越小该峰值越明显。为理清该噪声源产生机理, 采用了联合仿真法, 即将计算流体力学软件STAR CCM+中得到的管道内壁和挡板壁面上的流体压力导出, 在声学计算软件Simcenter 3D中将其转换为偶极子声源, 仿真其在管道内部和远场的噪声传播过程。管道内部声场云图表明, 噪声频谱中的峰值主要由风道中的帕克模态导致, 其频点位置及大小与挡板角度和流速有关, 此外还观察到了管道内的高阶模态。文中研究明确了内含挡板的有流管道的气动噪声特性和噪声源产生机理, 为后续从源头上实施降噪方案提供了重要依据。