Effect of seam characteristics on critical Reynolds number in footballs

In recent years, the design of footballs, including the number and shape of the panels forming the surface of footballs, has undergone a significant change. However, panels of varied shapes and seams are combined in complex ways to form the surface shape of footballs, and almost nothing is known abo...

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Autores principales:	Kiyoshi NAITO, Sungchan HONG, Masaaki KOIDO, Masao NAKAYAMA, Keiko SAKAMOTO, Takeshi ASAI
Formato:	article
Lenguaje:	EN
Publicado:	The Japan Society of Mechanical Engineers 2018
Materias:	aerodynamics air drag ball trajectory football reynolds number Mechanical engineering and machinery TJ1-1570
Acceso en línea:	https://doaj.org/article/594925692ebc4ce38ab533c0bac3eff4
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id	oai:doaj.org-article:594925692ebc4ce38ab533c0bac3eff4
record_format	dspace
spelling	oai:doaj.org-article:594925692ebc4ce38ab533c0bac3eff42021-11-26T07:14:14ZEffect of seam characteristics on critical Reynolds number in footballs2187-974510.1299/mej.17-00369https://doaj.org/article/594925692ebc4ce38ab533c0bac3eff42018-01-01T00:00:00Zhttps://www.jstage.jst.go.jp/article/mej/5/1/5_17-00369/_pdf/-char/enhttps://doaj.org/toc/2187-9745In recent years, the design of footballs, including the number and shape of the panels forming the surface of footballs, has undergone a significant change. However, panels of varied shapes and seams are combined in complex ways to form the surface shape of footballs, and almost nothing is known about the effect of these surface shapes on the football drag characteristics. The present study used a wind tunnel to study the relationship between the critical Reynolds number and the length, depth, and width of the panel joints (seams) of 10 most recent football types used in matches in recent years. The results show the tendency that the drag coefficient in the super-critical regime (30 m/s) of a football increases as the panel joint length increases. Moreover, the depth of the panel joint indicates the highest correlation with the critical Reynolds number (r = -0.71, p < 0.01) and is considered to be a strong and convenient indicator that expresses the roughness (large scale) of the football surface. This study reveals the drag characteristics of the latest footballs and enables some degrees of prediction of the critical Reynolds number for the latest football types and those that will be developed in the future.Kiyoshi NAITOSungchan HONGMasaaki KOIDOMasao NAKAYAMAKeiko SAKAMOTOTakeshi ASAIThe Japan Society of Mechanical Engineersarticleaerodynamicsair dragball trajectoryfootballreynolds numberMechanical engineering and machineryTJ1-1570ENMechanical Engineering Journal, Vol 5, Iss 1, Pp 17-00369-17-00369 (2018)
institution	DOAJ
collection	DOAJ
language	EN
topic	aerodynamics air drag ball trajectory football reynolds number Mechanical engineering and machinery TJ1-1570
spellingShingle	aerodynamics air drag ball trajectory football reynolds number Mechanical engineering and machinery TJ1-1570 Kiyoshi NAITO Sungchan HONG Masaaki KOIDO Masao NAKAYAMA Keiko SAKAMOTO Takeshi ASAI Effect of seam characteristics on critical Reynolds number in footballs
description	In recent years, the design of footballs, including the number and shape of the panels forming the surface of footballs, has undergone a significant change. However, panels of varied shapes and seams are combined in complex ways to form the surface shape of footballs, and almost nothing is known about the effect of these surface shapes on the football drag characteristics. The present study used a wind tunnel to study the relationship between the critical Reynolds number and the length, depth, and width of the panel joints (seams) of 10 most recent football types used in matches in recent years. The results show the tendency that the drag coefficient in the super-critical regime (30 m/s) of a football increases as the panel joint length increases. Moreover, the depth of the panel joint indicates the highest correlation with the critical Reynolds number (r = -0.71, p < 0.01) and is considered to be a strong and convenient indicator that expresses the roughness (large scale) of the football surface. This study reveals the drag characteristics of the latest footballs and enables some degrees of prediction of the critical Reynolds number for the latest football types and those that will be developed in the future.
format	article
author	Kiyoshi NAITO Sungchan HONG Masaaki KOIDO Masao NAKAYAMA Keiko SAKAMOTO Takeshi ASAI
author_facet	Kiyoshi NAITO Sungchan HONG Masaaki KOIDO Masao NAKAYAMA Keiko SAKAMOTO Takeshi ASAI
author_sort	Kiyoshi NAITO
title	Effect of seam characteristics on critical Reynolds number in footballs
title_short	Effect of seam characteristics on critical Reynolds number in footballs
title_full	Effect of seam characteristics on critical Reynolds number in footballs
title_fullStr	Effect of seam characteristics on critical Reynolds number in footballs
title_full_unstemmed	Effect of seam characteristics on critical Reynolds number in footballs
title_sort	effect of seam characteristics on critical reynolds number in footballs
publisher	The Japan Society of Mechanical Engineers
publishDate	2018
url	https://doaj.org/article/594925692ebc4ce38ab533c0bac3eff4
work_keys_str_mv	AT kiyoshinaito effectofseamcharacteristicsoncriticalreynoldsnumberinfootballs AT sungchanhong effectofseamcharacteristicsoncriticalreynoldsnumberinfootballs AT masaakikoido effectofseamcharacteristicsoncriticalreynoldsnumberinfootballs AT masaonakayama effectofseamcharacteristicsoncriticalreynoldsnumberinfootballs AT keikosakamoto effectofseamcharacteristicsoncriticalreynoldsnumberinfootballs AT takeshiasai effectofseamcharacteristicsoncriticalreynoldsnumberinfootballs
_version_	1718409718613934080

Effect of seam characteristics on critical Reynolds number in footballs

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