超低周波音の大気伝搬シミュレーション

概要

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Those program were made to simulate the propagation of low frequency noise that had caused a problem of environmental pollution from a tanker at a harbor. Using this program, the sound pressure level distribution of compound sound was analyzed considering wall position, sound reflection and diffraction. The following results were obtained througt the analysis and itscom-parision with some actual measurement data. The sound pressure levels were decreased in shadow zone at long wall, but this effects were almost canceled by the reflection of sound from other walls arrived there. In case of gradient wall (mountain etc.), where the height of sound source assumed 20m, the reflection dose not influence to the sound pressure level at recieved points excepts those on the wall. The propagated sound levels can approximatly be calculated by half sphericaldiffusion theory when the reflection from there walls is small. The sound pressure levels are almost not influenced by the change of mean absorption coefficient of ground and wall between 0.05 and 0.3. At the received points over the gradient wall, the propagated sound level increase.
独立行政法人海上技術安全研究所の論文
1988-01-30