Current Search: Traffic noise--Measurement (x)
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- Title
- ACOUSTIC SOURCE ASSESSMENT USING SOURCE BREAKDOWN.
- Creator
- SMART, RICHARD C., Florida Atlantic University, Glegg, Stewart A. L., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Knowledge of vehicle source heights is necessary for noise barrier design, but currently, no reliable method exists to measure this parameter. This study involves the development of system to evaluate source heights using a method known as the source breakdown technique. The first phase of this study consists of the demonstration of the source breakdown technique on loudspeakers in an anechoic chamber. The second phase involves tests outdoors using loudspeakers in the presence of ground...
Show moreKnowledge of vehicle source heights is necessary for noise barrier design, but currently, no reliable method exists to measure this parameter. This study involves the development of system to evaluate source heights using a method known as the source breakdown technique. The first phase of this study consists of the demonstration of the source breakdown technique on loudspeakers in an anechoic chamber. The second phase involves tests outdoors using loudspeakers in the presence of ground reflections. The third phase consists of an assessment of sources on a single vehicle. In the first two phases, source breakdown results are compared with actual measurements for verification. Noise and source mislocation errors are considered, as well as methods to reduce their detrimental effects.
Show less - Date Issued
- 1987
- PURL
- http://purl.flvc.org/fcla/dt/14393
- Subject Headings
- Traffic noise--Measurement
- Format
- Document (PDF)
- Title
- Measurement of source height on moving highway vehicles.
- Creator
- Yoon, Jong Rak, Florida Atlantic University, Glegg, Stewart A. L., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
A measurement method for the equivalent noise source height of an arbitrary distribution of moving noise sources is developed to investigate the highway vehicle equivalent source heights which are currently used by the FHWA for noise barrier design. The study is intended to provide information required to improve this noise barrier design code. The equivalent point source position is defined for an arbitrary distribution of acoustic sources above a reflecting plane and a method for its...
Show moreA measurement method for the equivalent noise source height of an arbitrary distribution of moving noise sources is developed to investigate the highway vehicle equivalent source heights which are currently used by the FHWA for noise barrier design. The study is intended to provide information required to improve this noise barrier design code. The equivalent point source position is defined for an arbitrary distribution of acoustic sources above a reflecting plane and a method for its measurement using a microphone array is developed. The normalized errors of the measured equivalent source heights are defined including the effects of background noise, the geometric near field, source size, and source directionality. Normalized errors of the measured source heights obtained by a numerical simulation for each parameter lead to optimization of the microphone spacing and to the design of an array of microphones which give the equivalent source height as a function of frequency. The method is then applied to the measurement of the equivalent source height of stationary loudspeakers and is shown to give results which are consistent with theoretical predictions. The effect of the Doppler frequency shift of moving vehicles is investigated using a loudspeaker mounted on the roof of a moving car. If the speed of a moving noise source is less than 97 kph, the error due to the Doppler frequency shift was found to be negligible. Results of measurement on highway vehicles show that the noise source heights for heavy trucks and for automobiles are different from those used currently by the FHWA.
Show less - Date Issued
- 1990
- PURL
- http://purl.flvc.org/fcla/dt/12247
- Subject Headings
- Traffic noise--Mathematical models, Traffic noise--Measurement--Mathematical models, Noise barriers--Mathematical models
- Format
- Document (PDF)