Method for Measuring Vehicle Noise Source Heights and Subsource Spectra

Coulson, Robert

doi:10.3141/1559-02

Cited by 2 publications

(3 citation statements)

References 2 publications

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“…The mean source heights determined in this research were slightly lower than those reported from previous studies completed in the United States. In the mid-1990s, Florida Atlantic University performed a large number of vehicle noise source vertical distribution tests on active roadways by using an eight-element linear array (8). With this system, source height was calculated by means of ground plane reflection-interference effects.…”

Section: Average Profiles and Mean Source Heightsmentioning

confidence: 99%

Measurement of Vertical Distribution of Truck Noise Sources during Highway Cruise Pass-Bys by Acoustic Beam Forming

Donavan¹,

Rymer

2009

Transportation Research Record: Journal of the Transportation R

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A measurement program was completed to determine the vertical distribution of heavy-truck noise sources for pass-by events on an in-service highway for vehicles operating under cruise conditions. In addition to data on heavy trucks, some data were obtained for medium trucks and light-duty vehicles. The measurements were performed with acoustic beam forming, which provided visualization of the sound radiation of passing vehicles as well as means for calculating the vertical distribution of noise source level. The data set includes pass-by events for 125 heavy trucks, 30 medium trucks, and nine light vehicles operating nominally at 55 mph on two asphalt surfaces. The purposes of the research were to compare the source height splits assumed in the FHWA traffic noise model (TNM) to the results of this work, examine the acoustic benefit of sound walls designed to block the line of site of truck exhaust outlets, and obtain a better understanding of truck noise sources. For heavy trucks, the pass-by noise is dominated by tire noise produced by the drive axles, with other secondary sources related to the power train occurring in some cases. Noise from elevated exhaust outlets was not observed except in one or two special cases. For all vehicle types, ground level sources (tire noise) produced the highest noise levels. Furthermore, the vertical source distributions were found to be virtually identical for heavy and medium trucks. For truck and light vehicles, it appeared that the current source height splits assumed in TNM may be biased toward higher upper-source strength.

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Section: Average Profiles and Mean Source Heightsmentioning

confidence: 99%

Measurement of Vertical Distribution of Truck Noise Sources during Highway Cruise Pass-Bys by Acoustic Beam Forming

Donavan¹,

Rymer

2009

Transportation Research Record: Journal of the Transportation R

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“…Unfortunately sources close to the ground are expected when working with terrestrial transportation sources. Moreoverin [4,5,6] the 95% confidence interval on the computed equivalent height is greater than 0.2 m. An error of 0.2 monthe source height can result in prediction errors as high as 3dBa tl arge distances. Pallas used classical array signal processing with av ertical array on passenger cars [7,8] to drawam ap of physical sources with the same limitations on accuracy.…”

Section: Introductionmentioning

confidence: 96%

“…The frequencydependent equivalent source height of ad istribution of sources is derivedfrom cross-spectrum densities between microphones. Coulson [6] applied this method to al arge set of vehicle pass-bys. This measurement principle makes it difficult to cope with sources less than 0.5 ma bove the ground.…”

Section: Introductionmentioning

confidence: 99%

Source Height Determination for Several Sources at the Same Height

Golay¹,

Dutilleux²,

Écotière³

2010

Acta Acustica united with Acustica

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Equivalent acoustic source height is an important parameter for accurate predictions of the acoustic impact of transportation infrastructures. Research has shown that this parameter can be obtained from at wo-microphone technique in the case of one broadband omnidirectional point source above an homogeneous ground, modeled as aDelany-Bazleyabsorber.Itisshown in this paper that this method can be generalized to n broadband sources with same height, above an homogeneous ground or aground with an impedance discontinuity.All sources are considered to have the same emission spectrum. The method is based on the comparison of the leveldi fference spectrum between twomicrophones -hereinafter called attenuation spectrum -measured and computed. Numerical and experimental validations confirm the reliability of the method for controlled noise sources. Furthermore, it is demonstrated that qualitative assessment of ground parameters is sufficient to obtain an accurate source height determination. PACS no. 43.28.Hr,43.50.Lj ©S.Hirzel Verlag · EAA 863 ACTA ACUSTICA UNITED WITH ACUSTICA Golay et al.:S ource height determination Vol. 96 (2010)

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Method for Measuring Vehicle Noise Source Heights and Subsource Spectra

Cited by 2 publications

References 2 publications

Measurement of Vertical Distribution of Truck Noise Sources during Highway Cruise Pass-Bys by Acoustic Beam Forming

Measurement of Vertical Distribution of Truck Noise Sources during Highway Cruise Pass-Bys by Acoustic Beam Forming

Source Height Determination for Several Sources at the Same Height

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