Magnus Effect (Curved Balls Explained) - Roberto Carlos Free Kick 1997

[Integza]

The Magnus effect, is the effect that explains whys a ball with rotational motion tends to have a curve path through the air.

 

In this video i try to give the a good explanation of the magnus effect through simple analogies like a scooter on a ramp and the air being sucked out of a bottle. 

 

I also relate this effect with the historical Roberto Carlos free kick from the the game of 1997 against France.

 

The objective of this video is to explain the Magnus effect without using much technical terminology and in the most intuitive way possible.

 

https://www.youtube.com/watch?v=t7MsYZgtXXo

 

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https://www.youtube.com/channel/UC2avWDLN1EI3r1RZ_dlSxCw

 

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[CraigD]

Welcome to Hypography, Integza, and good luck with your YouTube channel! :thumbs_up Though I imagine making videos takes a lot of your time, I hope you can spend some time discussing the Magnus effect in this thread. Please feel free to post a thread in the introductions forum to tell us about yourself.

 

I had fun watching your video. The best part, IMHO, was where you had a few big blue balls representing air molecules impacting a spinning football (what we call a soccer ball in the US), with a red triangle showing the low pressure zone behind the ball accelerating it. I liked you approach of explaining everything in terms of pressure.

 

However, what that animation showed wasn’t what actually happens with a spinning ball moving through air. It showed a left-moving, anticlockwise-spinning ball – a ball with “topspin” – having not only a rightward horizontal drag force component, but an upward vertical component, which would tend to make it hitting the ground later than an unspinning ball. A ball with topspin experienced a downward force. A left-moving, clockwise-spinning ball – one with “back” or “underspin” – experiences an upward force, as show in this sketch from the Wikipedia article Magnus effect:

Notice that the low pressure triangular “tail” in this diagram points right and down, but the actual net force pointing right and up

 

What I think you need to do to have your big blue balls animation show the correct, downward Magnus force, is show that the greater number (due to their rightward movement being slowed by the spinning football) of blue balls pushing downward from above the ball push down more than the lesser number of balls pushing up from below.

 

In terms of named aerodynamic effects, this shows that the Magnus effect is related to the Bernoulli effect. The upward force in the Bernoulli effect is due to air flowing faster above an airfoil because its induced to travel a greater distance, while with the Magnus effect, the faster flow air is due to the spinning cylinder or ball dragging it.

 

A game who’s ball shows the Magnus effect more dramatically than either football or baseball is Trac Ball, which better known as a toy than a sport.

https://www.youtube.com/watch?v=gJbOiM5dmbQ

is a pretty good video showing people throwing the special Trac Ball ball around with its special racquets.

[Integza]

Hi CraigD ;) Thank you for the compliments.

 

I understand what you are talking about, in my animation the low pressure zone  position is exaggerated  to give emphasis to the deviation of the low pressure zone.

Actually the low pressure zone should be limited by the lines pointed out by the black arrows:

 

https://lh3.googleusercontent.com/z3sHaP9NpKuTrL6gWCdfyv6jzJt9S9QYLKp-t_gUdFUIxiqilJ9Xkp9mltNvgOM8a2M6Lg=s153

 

Was a decision I made to make the animation simpler and more easy to understand, i hope it didn't  confuse anyone trying to understand but i will  put an annotations on video referring this.