Why Golf Balls Have Dimples

This is a fast, non-technical explanation of the basic aerodynamics of modern golf balls, for those who wonder why golf balls have dimples.

Category:

Education

Tags:

• golf
• dimples
• physical
• science

[squishyalt]

Completely and utterly wrong. This is the problem with using the internet to do your research. Just any explanation is not necessarily the correct one.

Please correct your supposition and re-up your video.

[Davidson1956]

Well, you're very persuasive. And to think that a PhD physicist and best selling physics textbook author liked my explanation and was thinking of adapting it for use in his next textbook. Perhaps you can enlighten us as to why all of it is so utterly wrong?

[zlovering]

Dimples create turbulence, which in turn decreases drag. Turbulent flow re-energizes the boundary layer causing it to remain attached for longer and decreasing the aft low pressure area. That's really what makes the ball go farther. Additionally, ANY sphere that spins, no matter how smooth, will develop lift since the flow velocity at the surface is zero (no slip boundary condition). Since it doesn't slip it will still carry the air around as explained.

[Davidson1956]

Thanks for your insights! It sounds like you have greater expertise on fluid dynamics than I do.

[jmtp79]

This being the case, how come ping-pong balls are smooth, yet they still have an enormous amount of curve due to the spin that is put on them when they are hit? The video claims that balls that are smooth will not curve when thrown with a spin.

[Davidson1956]

Great question! I wish I had someone like you in each of my classes.

Ping pong balls are not glossy smooth. They have a tiny bit of roughness to their exterior, plus they also pick up a little dirt. That would cause no curve to speak of for a golf ball made with a similar cover, but the mass of a ping pong ball is so slight in comparison that it takes very little difference in air pressure to make it curve.

[goweb172]

@zlovering I see what you're saying that any rotating cylinder/sphere will produce lift in an airflow (Magnus Effect), wouldn't the dimples encourange an even stronger Magnus Effect/circulation?

[sirfreakman]

@Davidson1956 Thanks for the explanation!

[20051470]

@squishyalt You're right, this is the wrong explanation. zlovering got it right.

[20051470]

@zlovering You're correct. His explanation is not the right one.

[bob1012112]

@Davidson1956 don't feed the trolls buddy, great work!

[DjRjSolarStar]

Good explanation, follows along the line of thought that I was going towards.

[CainNZ]

@TheSecularAdvocate I believe "the fact the ball is spinning that makes dimples so useful" is exactly what Davidson1956 is trying to portray in this video. I also believe Davidson1956 is trying to explain that when placing a backspin on the ball, the dimples in turn magnify the magnus effect.

[TheSecularAdvocate]

@TheArfdog You are dead right. I've seen loads of nonsense written by "experts" on aerodynamics who analyse the aerodynamic effect of a golf ball without realising that it's the fact that the ball is spinning that makes dimples so useful. A deeper dimpled ball creates more lift and a steeper drop on a nicely struck shot - it also emphasises any fade or draw spin.

[TheSecularAdvocate]

@CainNZ The experiments you'd like to see were done in the 1960's by ballistics experts at the behest of the R&A in Britain and written up in a book called "The search for the perfect swing"

[CainNZ]

@jk28416 going by your theory (or Euler's), how about you post a video response of a golf ball being hit within controls (force in which the ball is hit, inside so there's no wind, etc). One filmed shot with spin, another without. Distance traveled being the measure. Theories are all fine, but practical testing with results is true science.