| Project/Area Number |
07650695
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Architectural environment/equipment
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| Research Institution | Meijo University |
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Principal Investigator |
YOSHIHISA Koichi Meijo Univ., Fac.of Sci.& Tech., Assoc.Prof., 理工学部, 助教授 (60158491)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1996: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1995: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | enviromental assessment / noise propagation / field measurement / prediction method / numerical simulation / weather / daytime / nighttime / 日変化 / 昼夜間 |
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| Research Abstract |
Concerning the noise problem in residential area caused by highway traffic, factories, airports and so on, the differences of noise level between day and night should be considered. The differences are supposed to be caused not only by the changes of the sound source characteristics but also by the changes of the sound propagation characteristics mainly due to the effect of vertival temperature gradient near the ground surface.
In order to examine the differences of sound propagation characteristics between day and the author carried out in the series of the field measurements and the numerical simulation.
The Measurements of sound propagation from a point source over a playing field were made night, in August, September and December. Two loud speakers were set at both ends of a base line over a distance of 200m. The four receiving points were set at the height of 1.2m of the ground above the base line. In the measurements, a total of 252 trails were made during 7 days. The measured data were compared with meteorological data measured at the site.
As a result of the measurements, It has been found that the octave sound levels from 250Hz to 4kHz during the nighttime are seriously higher than that during the daytime.
In order to explain the measured results, The calculation of sound propagation in various meteorological conditions were made based on the wave theory.
It has been found that the results of the measurement are in accordance with the theoretical consideration. A prediction model which is applicable not only during the daytime but also the nighttime has been proposed.
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