Effect of panel shape of soccer ball on its flight characteristics

Hong, Sungchan; Asai, Takeshi

doi:10.1038/srep05068

Cited by 40 publications

(38 citation statements)

References 15 publications

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“…In recent years, many aerodynamic studies on footballs have reported that the number, orientation, and shape of the football panels induce a significant effect on the drag characteristics of footballs (Goff and Carré, 2009, Hong and Asai, 2014, Hong and Asai, 2017, Hong et al, 2015, Passmore et al, 2008, Tuplin et al, 2012. The present study demonstrated trends similar to these earlier works.…”

Section: Ball Typesupporting

confidence: 81%

Effect of seam characteristics on critical Reynolds number in footballs

Naito

Hong

Koido

et al. 2018

Mechanical Engineering Journal

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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.

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Section: Ball Typesupporting

confidence: 81%

Effect of seam characteristics on critical Reynolds number in footballs

Naito

Hong

Koido

et al. 2018

Mechanical Engineering Journal

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“…Similar trajectories have finally been observed in soccer by Barber et al [8]. In this sport, zigzag paths occur with particular balls (such as the official match ball of the 2010 FIFA World Cup, Jabulani) when kicked with no spin [9]. Finally, knuckleballs have also been reported in cricket for a delivering speed of about 30 m s −1 [10].…”

Section: Introductionsupporting

confidence: 65%

Physics of knuckleballs

et al. 2016

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Zigzag paths in sports ball trajectories are exceptional events. They have been reported in baseball (from where the word knuckleball comes from), in volleyball and in soccer. Such trajectories are associated with intermittent breaking of the lateral symmetry in the surrounding flow. The different scenarios proposed in the literature (such as the effect of seams in baseball) are first discussed and compared to existing data. We then perform experiments on zigzag trajectories and propose a new explanation based on unsteady lift forces. In a second step, we exploit wind tunnel measurements of these unsteady lift forces to solve the equations of motion for various sports and deduce the characteristics of the zigzags, pointing out the role of the drag crisis. Finally, the conditions for the observation of such trajectories in sports are discussed.

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“…Here, F D is the hydrodynamic drag force on the sphere of radius R traveling with velocity U in a fluid of density ρ and dynamic viscosity μ. Controlling the onset of the drag crisis, with dimples on a golf ball or threads on a soccer ball and baseballs, increases their range and stabilizes their trajectories, but can also save propulsive energy in maritime vessel related applications [2][3][4].…”

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confidence: 99%