Prediction of the Absorption Characteristics of Non-Uniform Acoustic Absorbers with Grazing Flow

Ou, Yang; Zhao, Yonghui

doi:10.3390/app13042256

Cited by 6 publications

(2 citation statements)

References 44 publications

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“…However, Toulorge 35 selected a more complex acoustic impedance extraction method, the calculation method occupied a higher computer memory. Ou 36 developed the impedance boundary Navier–Stokes equation (IBNSE) method to predict the absorption characteristics of acoustic ducts with grazing flow.…”

Section: Introductionmentioning

confidence: 99%

Acoustic impedance extraction method and acoustic characteristics analysis of perforated plates under grazing flow

Wen,

Wu,

et al. 2023

Journal of Low Frequency Noise, Vibration and Active Control

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As an important component of inlet and exhaust mufflers, the acoustic characteristics of perforated components are inevitably affected by the flow of air. Therefore, obtaining the acoustic impedance of the perforated element under airflow conditions is a prerequisite for accurate calculation of the muffler’s muffling performance. In this work, the frequency domain linear Navier–Stokes (L-NS) method is used to extract the acoustic impedance of perforated plates under grazing flow. The predicted perforated acoustic impedance is consistent with the calculation results of published acoustic impedance expression, and the impedance boundary condition is defined to calculate the transmission loss (TL) of the perforated muffler, which agrees well with the experimental results and verifies the accuracy of the method. The effect of perforation angles on the transmission loss of mufflers in different Mach numbers ( Ma) and aperture plate thickness ratio ( dh/ tp) is analyzed by the frequency domain L-NS method. The results show that when 1≤ dh/ tp<2 and Ma≤2, the effect of perforation angles on the muffler performance is obvious, and the angle tilted upstream shifts the resonant frequency to a lower frequency while its corresponding peak value is also increased. As an engineering application, it has certain significance for the prediction of muffler muffling performance and the regulation of the muffling frequency band.

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Section: Introductionmentioning

confidence: 99%

Acoustic impedance extraction method and acoustic characteristics analysis of perforated plates under grazing flow

Wen,

Wu,

et al. 2023

Journal of Low Frequency Noise, Vibration and Active Control

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“…Experimental methods, carrying out measurements of liner samples with different geometric characteristics [1-5]; • Numerical solutions based on mathematical models describing the propagation of sound in a duct with resonators attached to it [6][7][8][9][10] (in fact, by conducting a virtual experiment for each sample with individual geometric parameters); • Calculations based on the semi-empirical theory [11][12][13][14][15][16][17][18][19][20][21].…”

mentioning

confidence: 99%

Comparison of Semi-Empirical Impedance Models for Locally-Reacting Acoustic Liners in a Wide Range of Sound Pressure Levels

et al. 2023

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A comparison is considered of the experimentally obtained impedance of locally reacting acoustic liner samples with the impedance calculated using semi-empirical Goodrich, Sobolev and Eversman models. The semi-empirical impedance models are outlined. In the experiment, the impedance is synchronously measured on a normal incidence impedance tube by the transfer function method and Dean’s method. A modification of the conventional normal incidence impedance tube is proposed to obtain these measurements. To automate the measurements, a program code is developed that controls sound generation and the recording of signals. The code includes an optimization procedure for selecting the voltage on an acoustic driver, providing the required sound pressure level on the face of the sample at different frequencies. The geometry of acoustic liner samples and specifics of synchronous impedance measurements by the aforementioned methods are considered. Experiments are performed at sound pressure levels from 100 to 150 dB in the frequency range of 500–3500 Hz. A comparative analysis of semi-empirical models with the experimental results at different sound pressure levels is carried out.

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Numerical simulation of sound attenuation in an acoustically lined duct in high-temperature air flows

Jiang,

Zhao

2024

AIP Advances

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Noise reduction structures are important for the vibration and noise reduction design of aerospace engines. The design of noise-reducing structures often needs to be quickly evaluated via numerical simulations. Hence, the simulation results of the corresponding system are very important for guiding the design of noise-reducing structures. High temperature is one of the key environmental factors that need to be considered when evaluating the sound attenuation process via numerical methods. In this study, numerical simulations of acoustic wave propagation on an acoustic liner structure considering air temperature variations are carried out by using compressible Navier–Stokes equations and the ideal gas equation of state. The results showed that the effect of temperature on sound attenuation under grazing flow conditions is complex. Moreover, an increase in temperature will reduce the transmission loss of the acoustic liner in the grazing flow at high air speed.

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Prediction of the Absorption Characteristics of Non-Uniform Acoustic Absorbers with Grazing Flow

Cited by 6 publications

References 44 publications

Acoustic impedance extraction method and acoustic characteristics analysis of perforated plates under grazing flow

Acoustic impedance extraction method and acoustic characteristics analysis of perforated plates under grazing flow

Comparison of Semi-Empirical Impedance Models for Locally-Reacting Acoustic Liners in a Wide Range of Sound Pressure Levels

Numerical simulation of sound attenuation in an acoustically lined duct in high-temperature air flows

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