Magnus effect - GIF

**Altair** · Feb 6, 2019, 10:30 PM

Named after the German physicist Heinrich Gustav Magnus, the Magnus effect is a phenomenon where the path of the spinning object is deflected due to the difference in pressure of the fluid on opposite sides of the spinning object.

Previously:

Nitinol paper clip returns to form after bending - GIF
Archimedes' screw sticks motion - GIF

**jimfols** · Feb 7, 2019, 10:22 PM

I never played golf but I've heard the dimples in the balls are there for a reason.

**PJs** · Feb 8, 2019, 02:56 PM

Nice Jon, I always called it English...

**tonyfoale** · Feb 10, 2019, 02:23 AM

Originally Posted by jimfols

I never played golf but I've heard the dimples in the balls are there for a reason.

I have never played golf either but the dimples increase the range of a ball by a large margin. The dimples have an aerodynamic effect, they energise the boundary layer and delay the point of flow separation. This reduces the size of the wake, drag is closely proportional to the size of the wake, so in simple terms the dimples reduce aerodynamic drag.

**RV Hecker** · Feb 10, 2019, 10:27 AM

Shuberth made a helmet at one point that had dimples on the top. BMW Motorrad sold it, I recall....

RV

**tonyfoale** · Feb 10, 2019, 12:41 PM

Originally Posted by RV Hecker

Shuberth made a helmet at one point that had dimples on the top. BMW Motorrad sold it, I recall....

RV

Some misinformed people have even made motorcycle fairings with dimples but in all the examples that I have seen the dimples have been sized badly. There are other methods that can be used to delay the separation point on vehicles. You don't see dimples on aircraft. Vehicles are very different to golf balls.