{"id":387,"date":"2018-06-15T12:39:02","date_gmt":"2018-06-15T15:39:02","guid":{"rendered":"http:\/\/accuracyfea.com\/?p=387"},"modified":"2021-11-02T13:10:07","modified_gmt":"2021-11-02T16:10:07","slug":"el-efecto-magnus-y-la-pelota-de-la-copa-mundial-de-la-fifa","status":"publish","type":"post","link":"https:\/\/accuracyfea.com\/en\/2018\/06\/15\/el-efecto-magnus-y-la-pelota-de-la-copa-mundial-de-la-fifa\/","title":{"rendered":"The Magnus Effect and the FIFA World Cup \u2122 Match Ball"},"content":{"rendered":"

The Magnus Effect and the FIFA World Cup \u2122 Match Ball<\/span><\/h2>\n

An analysis of the Magnus effect by the COMSOL team for the 2014 FIFA World Cup<\/b><\/span><\/p>\n

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June 12, 2014<\/em><\/p>\n

Author:<\/strong> Ed Fontes<\/em><\/p>\n

URL: <\/strong>The Magnus Effect and the FIFA World Cup\u2122 Match Ball<\/a><\/p>\n

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The Beckham and Maradona curl obtained with the inside of the soccer cleat (football boot), and the curl by Eder, Nelinho, and Roberto Carlos with the outside of the cleat, is due to the Magnus effect<\/em>. The effect is named after the scientist who first observed it in a laboratory in the 1850s. The Magnus effect explains the side-force on a sphere that is both rotating and moving forward. We\u2019ll use it to analyze the FIFA World Cup\u2122 match ball.<\/p>\n

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Where Sports Meet Engineering<\/span><\/span><\/h3>\n

Like many kids around the world, my dream was to become a professional soccer player, or football as it\u2019s called outside the U.S., Canada, and Australia. However, as a nerdy kid, I also had two other main interests: cars and science.<\/p>\n

I remember being obsessed with the aerodynamics of cars in the early 1980s. In particular, the drag coefficient in competition and revolutionary aerodynamic designs between Audi and Ford. I was also keen to understand and achieve the specific curl of the ball when violently hitting it with the outside of my cleat. Engineering science was the glue that unified these interests later in life. Now, in preparation for the FIFA World Cup\u2122, I will share some of my CFD analyses of the match ball with you.<\/p>\n

Spin and Lack of Spin<\/span><\/span><\/h3>\n

The spinning of the ball has a stabilizing effect on the flow around it and thereby on its trajectory. But, let\u2019s begin with a case where there is little or no spin.<\/p>\n

If there is no spin, a Karman vortex street is formed behind the ball. The ball will then be subjected to force fluctuations with the detachment of vortices behind it. The wakes formed behind the ball not only increase the drag, they also contribute to the swerves that can be observed by anybody who has kicked a beach ball or been in the flight path of a knuckleball thrown by a baseball player. This semichaotic pattern can be partially explained in a transient simulation using the CFD Module.<\/p>\n

The figure and animation below show the Karman vortices behind a ball rotating counterclockwise with the same velocity at the equator as its forward movement, i.e., at the relatively low spin value. The animation is recorded on a corresponding 2D problem of a cylinder, which qualitatively shows the same effect.<\/p>\n

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