Aerodynamic drag of modern soccer balls

Abstract

Soccer balls such as the Adidas Roteiro that have been used in soccer tournaments thus far had 32 pentagonal and hexagonal panels. Recently, the Adidas Teamgeist II and Adidas Jabulani, respectively having 14 and 8 panels, have been used at tournaments; the aerodynamic characteristics of these balls have not yet been verified. Now, the Adidas Tango 12, having 32 panels, has been developed for use at tournaments; therefore, it is necessary to understand its aerodynamic characteristics. Through a wind tunnel test and ball trajectory simulations, this study shows that the aerodynamic resistance of the new 32-panel soccer ball is larger in the high-speed region and lower in the middle-speed region than that of the previous 14- and 8-panel balls. The critical Reynolds number of the Roteiro, Teamgeist II, Jabulani, and Tango 12 was ~2.2 × 105 (drag coefficient, Cd ≈ 0.12), ~2.8 × 105 (Cd ≈ 0.13), ~3.3 × 105 (Cd ≈ 0.13), and ~2.4 × 105 (Cd ≈ 0.15), respectively. The flight trajectory simulation suggested that the Tango 12, one of the newest soccer balls, has less air resistance in the medium-speed region than the Jabulani and can thus easily acquire large initial velocity in this region. It is considered that the critical Reynolds number of a soccer ball, as considered within the scope of this experiment, depends on the extended total distance of the panel bonds rather than the small designs on the panel surfaces.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-2-171) contains supplementary material, which is available to authorized users.

Effect of panel shape of soccer ball on its flight characteristics

“…These results are in accordance with a recent report on the drag characteristics of Brazuca and Jabulani12 and agree with the results from comparisons of Jabulani and Tango12 (official game balls for Euro 2012 with panel shapes identical to those of Cafusa)13. Our results also showed the same tendencies as those found in a prior study conducted on the four types of modern soccer balls (Jabulani, Teamgeist2, Tango12, and Roteiro)1. Preceding studies on drag characteristics of soccer balls reported that different types of soccer balls have different levels of aerodynamic forces91415.…”

Effect of seam characteristics on critical Reynolds number in footballs

“…The correlation coefficients of the panel joint length, width, and depth and the critical Reynolds numbers for these footballs were calculated (Figure 8). First, the correlation coefficient observed for the length of the panel joints and the critical Reynolds number was equally high, similar to that in our previous study (Asai and Seo, 2013), with r = -0.67 (p < 0.01). The correlation coefficient for the depth of the panel joints and the critical Reynolds number was found to exhibit a strong negative correlation (r = -0.71, p < 0.01).…”

“…Consequently, the relationship between the seam directions and the aerodynamics of the ball is a topic for future research. In particular, the critical Reynolds number for footballs made in recent years has been reported to be correlated to the length of the panel joints (Asai and Seo, 2013), and studying the football surface shapes and drag characteristics has been pointed out to be important. The present study revealed the effect of the length, depth, and width of the panel joints on the critical Reynolds number, and we believe that it provided important supporting data for future football designs.…”

An aerodynamic analysis of recent FIFA world cup balls

“…Total seam length and depth are currently believed to be the dominant measures of surface roughness for footballs [29]. Of the balls studied for this work the Jabulani has the lowest total seam length of 203 cm while the seam lengths of the Brazuca and Teamgeist are 327 cm and 345 cm respectively [30].…”