Array based measurement of radiated and absorbed sound intensity components

Hald, Jørgen; Mørkholt, Jakob; Hardy, Pierre; Trentin, D.; Bach‐Andersen, Martin; Keith, Graeme

doi:10.1121/1.2934043

Cited by 17 publications

(14 citation statements)

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“…The surface admittance of the source could be measured, for example, by using the methods given in Refs. 16,39,and 40 (in Ref. 39, a method for measuring the surface admittance when the source surface is non-locally reacting is also given).…”

Section: Separation Of Scattered and Radiated Fieldsmentioning

confidence: 99%

“…23 Further, the equivalent source method (ESM) using double-layer pressure measurements 24 or single-layer pressure-velocity measurements 25, 26 have all recently been developed for the same purpose. However, except for the boundary element method using a double-layer array 21 and SONAH using a two-layer handheld array, 16 none of the methods have taken into account the scattering effect of the source. Indeed, as indicated in Ref.…”

Section: Introductionmentioning

confidence: 99%

“…The spatial Fourier transform method-based SFST (Refs,(4)(5)(6)(7)(8)(9)(10), which has generally been used for measuring reflection coefficients [4][5][6][7][8] and separating incident and scattered fields, 9,10 was developed by Hallman and Bolton 11,12 to perform NAH in reflective environments, and by Williams 13 and Yu et al 14 to remove the effect of a disturbing source in NAH applications. Statistically optimized near-field acoustical holography (SONAH) has also been implemented by using a two-layer handheld array, 15,16 an array of pressure-velocity probes, [17][18][19] and a double-layer velocity transducer array. 20 The boundary element method can also be based on using a double-layer array 21,22 or Cauchy data.…”

Section: Introductionmentioning

confidence: 99%

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An equivalent source technique for recovering the free sound field in a noisy environment

Bolton²

2012

The Journal of the Acoustical Society of America

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In previous studies, a sound field separation technique based on the equivalent source method (ESM) was successfully applied to separate the incoming and outgoing fields composing a non-free field. However, if the incoming wave is scattered by the source surface, the outgoing field is not the field that would be generated by the source in a free field. The object of the present work was to provide an equivalent source technique that allows the recovery of that free field in a noisy environment. In this approach, the incoming and outgoing fields, including the scattered and directly radiated fields on the measurement surface, are separated to obtain the free-field pressure that would be radiated by the source in an anechoic environment. The recovered free-field pressure is then used to reconstruct the whole free field of the source by using near-field acoustical holography based on the ESM, which makes the results equivalent to those that could be obtained from a free-field measurement. A theoretical description of the technique is given first, and then three numerical cases are investigated to demonstrate the ability of the proposed method.

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Section: Separation Of Scattered and Radiated Fieldsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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An equivalent source technique for recovering the free sound field in a noisy environment

Bolton²

2012

The Journal of the Acoustical Society of America

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“…Results obtained with p-p or p-u SONAH were good. For measurements in small spaces, Hald et al 24 have proposed a method which uses a first measurement of the acoustical properties of the tested surface before performing operational measurements.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a separation method for source identification in small spaces

Braïkia

Melon

Langrenne

et al. 2013

The Journal of the Acoustical Society of America

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This paper investigates the efficiency of a field separation method for the identification of sound sources in small and non-anechoic spaces. When performing measurements in such environments, the acquired data contain information from the direct field radiated by the source of interest and reflections from walls. To get rid of the unwanted contributions and assess the field radiated by the source of interest, a field separation method is used. Acoustic data (pressure or velocity) are then measured on a hemispheric array whose base is laying on the surface of interest. Then, by using spherical harmonic expansions, contributions from outgoing and incoming waves can be separated if the impedance of the tested surface is high enough. Depending on the probe type, different implementations of the separation method are numerically compared. In addition, the influence of the walls' reflection coefficient is studied. Finally, measurements are performed using an array made-up of 36 p-p probes. Results obtained in a car trunk mock-up with controlled sources are first presented before reporting results measured in a real car running on a roller bench.

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“…In recent years, all kinds of vehicle manufacturers, for example, military, aircraft and mainly automobile industries, have noise reduction and control as one of the mail goals due to the increasing requirements for low noise emission. In an effort to decrease and control the interior noise and levels of vibration of not only the above-mentioned vehicles but also other equipment, devices and machines, many techniques have been developed: 1 noise source identification (NSI) techniques [2][3][4][5][6][7][8][9][10] and active and passive control methods. [11][12][13][14][15] In particular, passive controls can benefit of the use of innovative materials, such as piezoelectrics, shape memory alloys, 11 magnetostrictive materials 12 and chiral unit cells, [13][14][15][16][17][18] and their mechanical properties can be designed within very large range of modulus and Poisson's ratio values.…”

Section: Introductionmentioning

confidence: 99%

Loudness calculation procedure to study electronic steering column lock noise measurement

Maffiodo

Sesana

2019

Advances in Mechanical Engineering

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In the automotive field, the customer requirements for low interior noise and pleasant sound quality inside a vehicle are getting higher and higher. Various national and international regulatory authorities established and reviewed vehicle interior noise for the past years. Besides, lots of studies have shown that vehicle noise can influence the driver's perceptions and also his or her driving capabilities. To succeed in this scenario, all manufacturers are investing in technology and research in order to improve their component performance. Working on the noise source so as to reduce the seriousness of these noise problems can be really effective. However, various engineering techniques are available to deal with noise and sound-measuring instruments, and systems can help to identify the nature of the problem and they can also be helpful in determining the right procedure to analyse the noise problem. This work proposes a procedure to evaluate the noise originated from an electronic steering column lock device which is used to lock and unlock the steering wheel according to European safety requirements. In particular, different standards and requirements for loudness evaluation have been discussed and the formulation of a straightforward procedure, which can be used to evaluate the loudness according to costumer's requirements, is defined.

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Array based measurement of radiated and absorbed sound intensity components

Cited by 17 publications

References 0 publications

An equivalent source technique for recovering the free sound field in a noisy environment

An equivalent source technique for recovering the free sound field in a noisy environment

Evaluation of a separation method for source identification in small spaces

Loudness calculation procedure to study electronic steering column lock noise measurement

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