Identification of aerodynamic pressure fluctuations generated from high-speed trains passing an open section

It is known that pressure fluctuations are generated from intermediate vehicles of Shinkansen trains. Those pressure fluctuations involve the infra-sound phenomenon with a wavelength longer than several meters. Past studies showed that the infra-sound consists of the aerodynamic and structure-borne...

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Main Authors: Toki UDA, Toshiki KITAGAWA, Yusuke WAKABAYASHI, Takeshi KURITA
Format: Article
Language:Japanese
Published: The Japan Society of Mechanical Engineers 2019-10-01
Series:Nihon Kikai Gakkai ronbunshu
Subjects:
Online Access:https://www.jstage.jst.go.jp/article/transjsme/85/879/85_19-00179/_pdf/-char/en
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author Toki UDA
Toshiki KITAGAWA
Yusuke WAKABAYASHI
Takeshi KURITA
author_facet Toki UDA
Toshiki KITAGAWA
Yusuke WAKABAYASHI
Takeshi KURITA
author_sort Toki UDA
collection DOAJ
description It is known that pressure fluctuations are generated from intermediate vehicles of Shinkansen trains. Those pressure fluctuations involve the infra-sound phenomenon with a wavelength longer than several meters. Past studies showed that the infra-sound consists of the aerodynamic and structure-borne components, and the aerodynamic component is originated in the high-speed airflow around vehicles. The generating mechanism of the aerodynamic component, however, had been remained unclear. In this paper, a new methodology applicable to railway field tests is proposed to evaluate low-frequency aerodynamic sound less than 100Hz. A field test was conducted at a flat land without noise barriers, in which fifteen ultra-low frequency microphones constituting a linear microphone array were arranged in line along rails. In order to determine the frequency spectrum and distance decay rate, another five ultra-low frequency microphones were deployed at measurement points 8.7m to 50m apart from the nearest track center. The reason why the flat measurement site was selected was to suppress the bridge noise and focus on the aerodynamic noise during a train passage. On processing the microphone array signal to identify sound sources in field tests, much attention should be paid for the number of averaging; the number of averaging were limited so that sound source identification was difficult in practice. In this analysis, therefore, more than 100 trains were measured and ensemble-averaged to clarify the relationship between the number of averaging and precision of determining sound sources. Our field test campaign showed that low-frequency aerodynamic sound was locally distributed around all sections between two neighbouring bogies and pantograph sections.
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spelling doaj.art-d60b8946c0a8480dbda7a3ee46f5ec2f2022-12-22T04:35:16ZjpnThe Japan Society of Mechanical EngineersNihon Kikai Gakkai ronbunshu2187-97612019-10-018587919-0017919-0017910.1299/transjsme.19-00179transjsmeIdentification of aerodynamic pressure fluctuations generated from high-speed trains passing an open sectionToki UDA0Toshiki KITAGAWA1Yusuke WAKABAYASHI2Takeshi KURITA3Railway Technical Research InstituteRailway Technical Research InstituteEast Japan Railway CompanyEast Japan Railway CompanyIt is known that pressure fluctuations are generated from intermediate vehicles of Shinkansen trains. Those pressure fluctuations involve the infra-sound phenomenon with a wavelength longer than several meters. Past studies showed that the infra-sound consists of the aerodynamic and structure-borne components, and the aerodynamic component is originated in the high-speed airflow around vehicles. The generating mechanism of the aerodynamic component, however, had been remained unclear. In this paper, a new methodology applicable to railway field tests is proposed to evaluate low-frequency aerodynamic sound less than 100Hz. A field test was conducted at a flat land without noise barriers, in which fifteen ultra-low frequency microphones constituting a linear microphone array were arranged in line along rails. In order to determine the frequency spectrum and distance decay rate, another five ultra-low frequency microphones were deployed at measurement points 8.7m to 50m apart from the nearest track center. The reason why the flat measurement site was selected was to suppress the bridge noise and focus on the aerodynamic noise during a train passage. On processing the microphone array signal to identify sound sources in field tests, much attention should be paid for the number of averaging; the number of averaging were limited so that sound source identification was difficult in practice. In this analysis, therefore, more than 100 trains were measured and ensemble-averaged to clarify the relationship between the number of averaging and precision of determining sound sources. Our field test campaign showed that low-frequency aerodynamic sound was locally distributed around all sections between two neighbouring bogies and pantograph sections.https://www.jstage.jst.go.jp/article/transjsme/85/879/85_19-00179/_pdf/-char/enshinkansenbogie sectionsfield testlow-frequency aerodynamic noiselinear microphone array
spellingShingle Toki UDA
Toshiki KITAGAWA
Yusuke WAKABAYASHI
Takeshi KURITA
Identification of aerodynamic pressure fluctuations generated from high-speed trains passing an open section
Nihon Kikai Gakkai ronbunshu
shinkansen
bogie sections
field test
low-frequency aerodynamic noise
linear microphone array
title Identification of aerodynamic pressure fluctuations generated from high-speed trains passing an open section
title_full Identification of aerodynamic pressure fluctuations generated from high-speed trains passing an open section
title_fullStr Identification of aerodynamic pressure fluctuations generated from high-speed trains passing an open section
title_full_unstemmed Identification of aerodynamic pressure fluctuations generated from high-speed trains passing an open section
title_short Identification of aerodynamic pressure fluctuations generated from high-speed trains passing an open section
title_sort identification of aerodynamic pressure fluctuations generated from high speed trains passing an open section
topic shinkansen
bogie sections
field test
low-frequency aerodynamic noise
linear microphone array
url https://www.jstage.jst.go.jp/article/transjsme/85/879/85_19-00179/_pdf/-char/en
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AT toshikikitagawa identificationofaerodynamicpressurefluctuationsgeneratedfromhighspeedtrainspassinganopensection
AT yusukewakabayashi identificationofaerodynamicpressurefluctuationsgeneratedfromhighspeedtrainspassinganopensection
AT takeshikurita identificationofaerodynamicpressurefluctuationsgeneratedfromhighspeedtrainspassinganopensection