Aerodynamics of spinning and non-spinning tennis balls

Goodwill, Simon; Chin, S. B.; Haake, Steve

doi:10.1016/j.jweia.2004.05.004

Cited by 39 publications

(38 citation statements)

References 10 publications

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“…Mass reduction is dominated by a loss of felt and has been shown to increase with both impact speed and number of impacts [5]. The felt cover has been shown to degrade causing mass reduction and changes in fuzziness, in turn affecting the aerodynamic properties of the ball [7,8]. Furthermore, it has been acknowledged that balls may fall out of specification during use if the initial properties were close to the allowable limits when approval tested [9].…”

Section: Introductionmentioning

confidence: 99%

Characterisation of ball degradation events in professional tennis

Lane

Sherratt

et al. 2017

Sports Eng

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Tennis balls are acknowledged to degrade with use and are replaced at regular intervals during professional matches to maintain consistency and uniformity in performance, such that the game is not adversely affected. Balls are subject to the international tennis federation's (ITF) ball approval process, which includes a degradation test to ensure a minimum standard of performance. The aim of this investigation was to establish if the ITF degradation test can assess ball longevity and rate of degradation and determine if there is a need for a new degradation test that is more representative of in-play conditions. Ball tracking data from four different professional events, spanning the three major court surfaces, including both men's and women's matches were analysed. The frequency of first serves, second serves, racket impacts and surface impacts were assessed and the corresponding distribution of ball speed and (for surface impacts) impact angle was determined. Comparison of ball impact frequency and conditions between in-play data and the ITF degradation test indicated the development of a new test, more representative of in-play data, would be advantageous in determining ball longevity and rate of degradation with use. Assessment of data from different surfaces highlighted that grass court subjected the ball to fewer racket and surface impacts than hard court or clay. In turn, this appears to influence the distribution of ball speed on impact with the surface or racket, suggesting a surface-specific degradation test may be beneficial. As a result of these findings a new test protocol has been proposed, utilising the in-play data, to define the frequency of impacts and impact conditions to equate to nine games of professional tennis across the different surfaces.

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Section: Introductionmentioning

confidence: 99%

Characterisation of ball degradation events in professional tennis

Lane

Sherratt

et al. 2017

Sports Eng

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“…The consistency in drag coefficient for a non-spinning ball, using both experimental arrangements, lends confidence to the methodology used, especially considering that previous studies have found that the support arrangement used can have an effect on the measured drag coefficient [13].…”

Section: Aerodynamics Of a Smooth Spherementioning

confidence: 52%

“…The tare drag was found to be quite high, accounting for almost half the total drag measured on the ball-sting arrangement and although this amount of tare drag was unexpected, it was thought to be due to the relatively large cross-section of the sting, which had been designed to be sturdy and prevent any unwanted vibrations in the ball-sting arrangement. Work on tennis ball aerodynamics, since this research was carried out, reduced the tare drag slightly by redesigning the shrouding of the sting [13].…”

Section: The Effect Of Velocity On Dragmentioning

confidence: 99%

Understanding the Effect of Seams on the Aerodynamics of an Association Football

Carré

Goodwill

Haake

2005

Proceedings of the Institution of Mechanical Engineers, Part C:

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* Corresponding author ABSTRACTThe aerodynamic properties of an association football were measured using a wind tunnel arrangement. A third scale model of a generic football (with seams) was used as well as a 'mini-football'. As the wind speed was increased, the drag coefficient decreased from 0.5 to 0.2, suggesting a transition from laminar to turbulent behaviour in the boundary layer. For spinning footballs, the Magnus effect was observed and it was found that reverse Magnus effects were possible at low Reynolds numbers. Measurements on spinning smooth spheres found that laminar behaviour led to a high drag coefficient for a large range of Reynolds numbers and Magnus effects were inconsistent, but generally showed reverse Magnus behaviour at high Reynolds number and spin parameter. Trajectory simulations of free kicks demonstrated that a football that is struck in the centre will follow a near straight trajectory, dipping slightly before reaching the goal, whereas a football that is struck off centre will bend before reaching the goal, but will have a significantly longer flight time. The curving kick simulation was repeated for a smooth ball, which resulted in a longer flight time, due to increased drag, and the ball curving in the opposite direction, due to reverse Magnus effects. The presence of seams was found to encourage turbulent behaviour, resulting in reduced drag and more predictable Magnus behaviour for a conventional football, compared to a smooth ball.

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“…gravity, air resistance, Magnus force, and so on [3,4].The air resistance has the greatest impact on the flight trajectory of tennis.Many factors can affect the air resistance, including the Reynolds number of the flow field around the tennis, the compressibility of airflow, the turbulence characteristics, and the roughness of tennis surface [5][6][7]. The topspin tennis rotates along the corresponding direction because of the certain torque.…”

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confidence: 99%

Simulation Study of Aerodynamics during the Tennis Flight-A Case Study about the Topspin

Zhang¹,

Zhang²

2017

Proceedings of the 2017 5th International Conference on Mechatronics, Materials, Chemistry and Computer Engineering (ICMMCCE 20

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Abstract：The pressure distribution of airflow field around tennis and the characteristics of gas under various rotational velocities and flight conditions of tennis are simulated by the method of computational fluid dynamics(CFD) andtherelational software fluent 14.5 is used. Then the pressure distribution on the upper and lower surface of tennis are analyzed point by point. The results indicate thatdifference in pressure between the upper and lower surface of tennis increases with the increase of rotational speed,which can enhance the effect of Magnus force and causethe rapid falling of tennis.The increase of tennis speed will disorder the flow of the surrounding gas, result in the worse motion movement controllability oftennis, and change the motion trajectory. The static pressure distribution on the upper and lower surfaces oftennis is similar, but the change of pressure for the lower surface is slightly behind that of the upper surface. The drag coefficient and lift coefficient increase with the increase of the tennis speed and the rotational velocity, respectively. 1.IntroductionThe complex mechanical principle exists in the flight process of tennis, which includes many kinds of forces with synergistic continuous action. In this case, tennis always rotates following the specific direction.Forehand, as the most powerful weapon of tennis players, not only enhance the ball stability, but also improvestrongly bounced back height, which canincreasethe difficulty in return [1]. The most representative is that Rafael Nadal returns tennis with more than 3000rpm in clay court of theFrench Open, whichmakes Federer, Murray, Djokovic and many other players difficult to havethe high-quality counterattacks. The rotationalball drivesthe surrounding air, andthe airflow rate of the spherical side is greater than the other side. According to the Bernoulli equation, the pressure for the position with the greater velocity is relatively small, which can produce a force perpendicularly to the topspin flight direction [2]. Under the effect of this force, the opponent is difficult to predict andit is not easy to returntennis due to the extended flight time, decreased arc over net, and higher rebound after landing.Therefore, it is of great significance to study the characteristics offlying process for topspintennis.For the high-speed flyingtennis, the research on the topspin mainly bases on observing video of excellent players with different skills, but it is difficult to track the aerodynamics characteristics of the flight process only by qualitative analyses. In this paper, the aerodynamic characteristics of the different spherical positions of tennis in the flight process are simulated and analyzed. And the surrounding airflow field and its dynamic parameters during the flight process of atennis are studied by the method of computational fluid dynamics. This research work provides a reference for improving the tennis technical, skills tactical, daily training and competition. 2.Mechanical factors of the flight tennisA tennis dur...

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Aerodynamics of spinning and non-spinning tennis balls

Cited by 39 publications

References 10 publications

Characterisation of ball degradation events in professional tennis

Characterisation of ball degradation events in professional tennis

Understanding the Effect of Seams on the Aerodynamics of an Association Football

Simulation Study of Aerodynamics during the Tennis Flight-A Case Study about the Topspin

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