Directional Microphone Array for Acoustic Studies of Wind Tunnel Models

Soderman, P. T.; Noble, Stephen C.

doi:10.2514/3.59813

Cited by 23 publications

(4 citation statements)

References 2 publications

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“…The height was also in good agreement between the numerical simulation and the acoustic wind tunnel experiment for locating the sound source under the working conditions of 90 • and 180 • , but there was a slight difference between the front and rear positions. This is because for stationary sound sources, although the microphone array [20][21][22][23] can discriminate incoherent sources based on the traditional beamforming algorithm of delay superposition, the spatial resolution is relatively low, and the building model in this paper is relatively complex compared to the research model in the field of aerospace and vehicle engineering. Furthermore, there is a gap in the middle of the buildings that is not easily monitored by the microphone array, and the main airflow disturbance is generated in the gap.…”

Section: Comparison Results Between Simulated and Experimental Noise ...mentioning

confidence: 99%

Numerical Simulation Study of Aerodynamic Noise in High-Rise Buildings

2022

Applied Sciences

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In order to study the aerodynamic noise on the surfaces of high-rise buildings under the action of strong winds, this paper numerically simulated the sound pressure field on the surface of a high-rise building using the large-eddy simulation method combined with the acoustic analog method of FW-H (Ffowcs Williams–Hawkings) equation and obtained the intensity radiation distribution of sound pressure on the surface of the building to further identify the area with the maximum sound pressure intensity of the noise radiation and thus achieve the purpose of locating noise source. The accuracy of the numerical simulation results for aerodynamic noise obtained in this paper was then verified by comparing with the acoustic wind tunnel experimental results. The locations of noise source obtained by numerical simulation and acoustic wind tunnel experiment were in good agreement. The sound pressure intensity pulsation time course was measured by the acoustic wind tunnel experiment, and the noise sound pressure level spectrum of each part of the building surface was obtained by fast Fourier transform (FFT). Furthermore, the spectral characteristics of the noise sound pressure level were analyzed. The results of the sound pressure level spectrum of aerodynamic noise obtained from the numerical simulation were compared with the acoustic wind tunnel experimental results, which were found to be very similar. The analysis of the sound pressure level spectrum of aerodynamic noise on the building surface reveals that the numerical simulation results in the middle- and high-frequency bands of the spectrum are in good agreement with the acoustic wind tunnel experimental results, but there is a difference between those in the low-frequency bands and the acoustic wind tunnel experimental results. The microphone array used to locate the noise source in the acoustic wind tunnel was found to suffer non-eliminable measurement errors, which might be a potential reason for a reasonably slight difference between the experimental and numerical simulation results. The background noise in the low-frequency band of the acoustic wind tunnel sound pressure level spectrum was relatively large, while there was basically no background noise in the numerical simulation. This paper shows that the numerical simulation method combined with large-eddy simulation and acoustic analogy (FW-H) can calculate the aerodynamic noise intensity at various points on the surfaces of high-rise buildings and reasonably predict the location of sound source. In addition, the numerical simulation results are similar to the acoustic wind tunnel experimental results in most frequency bands.

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Section: Comparison Results Between Simulated and Experimental Noise ...mentioning

confidence: 99%

Numerical Simulation Study of Aerodynamic Noise in High-Rise Buildings

2022

Applied Sciences

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“…Therefore, there is a direct relationship between the number of sensors and the gain in the signal-to-noise ratio (SNR). Beamforming has been used to characterize noise sources from far-field pressure measurements in various applications [9][10][11][12][13][14]. For example, passby noise from a vehicle has been measured and visualized using beamforming [12].…”

Section: Introductionmentioning

confidence: 99%

A comparison of near-field beamforming and acoustical holography for sound source visualization

Cho

Roan

Bolton

2009

Proceedings of the Institution of Mechanical Engineers, Part C:

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Acoustical holography procedures make high-resolution visualization possible via estimation of the sound intensity on surfaces closer to the sources than the near-field measurement surface. Another source localization technique, beamforming, has been used to estimate the direction of arrival of sound from sources that typically lie in the far-field. However, little work has been done using beamforming as a visualization technique based on near-field measurements. As a result, the performance of beamforming and acoustical holography in terms of source resolution capabilities has not been directly compared when using near-field measurements. In this work, point source beamforming was used to visualize sources based on near-field measurements. Acoustic intensity estimated from beamformed pressure measurements was compared with the absolute intensity estimated using acoustical holography techniques. In addition to noise-free, anechoic simulations, cases of measurement pressure with random noise were generated and used to compare source resolution accuracy of acoustical holography and beamforming techniques in the presence of measurement noise. It was found that intensity estimated using acoustical holography provided the clearest image of sources when the measurement surface was conformal with the source geometry. However, sources can be resolved more accurately using near-field beamforming than acoustical holography at high frequencies when the sources are not located perfectly on a surface conformal with the measurement geometry.

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“…Another source localization technique, beamforming, has been used to estimate the direction of arrival of sound from sources that typically lie in the far field of the measurement array [10]. Beamforming has been used for noise source localization and characterization from far-field measurements in a variety of applications [11][12][13][14][15][16][17][18]. For example, impulsive sources were measured in noisy environments and were successfully localized [15].…”

Section: Introductionmentioning

confidence: 99%

Dual surface beamforming and acoustical holography for sound field visualization in reverberant environments

Cho

Roan

Bolton

2009

Proceedings of the Institution of Mechanical Engineers, Part C:

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Near-field acoustical holography is a technique that has been widely used to visualize noise sources from pressure measurements in spaces that can be assumed to be anechoic or semi-anechoic. Previously, a dual surface acoustical holography procedure based on making measurements on two surfaces between the source and a reflecting surface was introduced to remove the effects of reverberation. Little work has been performed in which beamforming has been used to visualize sources based on dual surface, near-field measurements in a reverberant environment: such a procedure is described here. Because many practical measurement environments are not completely anechoic, the source resolution accuracy of dual surface acoustical holography and beamforming procedures in reverberant environments is compared here by using numerical simulations. It has been found that dual surface acoustical holography provides the clearest representation of the source location when sound waves radiating from the source and the reflected waves are propagating in the opposite directions and when the measurement surfaces are conformal with the source geometry. However, it has also been found that dual surface beamforming provides more consistent source resolution performance regardless of the relative direction of wave propagation of the source and reflected waves.

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Directional Microphone Array for Acoustic Studies of Wind Tunnel Models

Cited by 23 publications

References 2 publications

Numerical Simulation Study of Aerodynamic Noise in High-Rise Buildings

Numerical Simulation Study of Aerodynamic Noise in High-Rise Buildings

A comparison of near-field beamforming and acoustical holography for sound source visualization

Dual surface beamforming and acoustical holography for sound field visualization in reverberant environments

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