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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Format: | Article |
Language: | Japanese |
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The Japan Society of Mechanical Engineers
2019-10-01
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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. |
first_indexed | 2024-04-11T08:13:05Z |
format | Article |
id | doaj.art-d60b8946c0a8480dbda7a3ee46f5ec2f |
institution | Directory Open Access Journal |
issn | 2187-9761 |
language | Japanese |
last_indexed | 2024-04-11T08:13:05Z |
publishDate | 2019-10-01 |
publisher | The Japan Society of Mechanical Engineers |
record_format | Article |
series | Nihon Kikai Gakkai ronbunshu |
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 |
work_keys_str_mv | AT tokiuda identificationofaerodynamicpressurefluctuationsgeneratedfromhighspeedtrainspassinganopensection AT toshikikitagawa identificationofaerodynamicpressurefluctuationsgeneratedfromhighspeedtrainspassinganopensection AT yusukewakabayashi identificationofaerodynamicpressurefluctuationsgeneratedfromhighspeedtrainspassinganopensection AT takeshikurita identificationofaerodynamicpressurefluctuationsgeneratedfromhighspeedtrainspassinganopensection |