Sabena332 From , joined Dec 1969, posts, RR:
Reply 2, posted (10 years 3 months 2 weeks 2 days 10 hours ago) and read 2494 times:
Quoting Sidewinder (Thread starter): I was once told that if a golf ball didn't have dimples it would fly as far. Has anyone heard that?
This is true, my father knows some guy who is the president of the golf club in my parent's hometown, I asked him also why a golfball has these dimples and he told me that it is flying further because of them. Don't ask my why, I have no clue about aerodynamic.
It would NOT fly as far. Dimples help intially to provide grip to the club, hence increasing contact time. This phenomenon, while important to spin, and perhaps distance, is overshadowed by the increase in lift afforded by the dimples.
Believe it or not, turbulent flow (not normally desirable in scenarios such as water flow) is very desireable in golf ball flight. The dimples help to make the air flow turbulent; hence increasing lift, thus flight distance.
777236ER From , joined Dec 1969, posts, RR:
Reply 5, posted (10 years 3 months 2 weeks 2 days 10 hours ago) and read 2474 times:
Quoting Logan22L (Reply 3): The dimples help to make the air flow turbulent; hence increasing lift, thus flight distance.
Nope, they delay separation, reducing drag.
Edit: Well, sort of. The dimples increase the dynamic viscoscity of the flowfield, which decreases the transition Reynolds number, which causes the boundary layer to become turbulent. The turbulent boundary layer is thicker, and crucially has more forward momentum than a laminar one (is energised). The greater forward momentum means the flow separates later. The delay in separation causes a smaller wake, and hence a smaller region of low static pressure on the trailing face of the golfball, relative to the leading face. For minimum drag, you want the trailing face pressure to be as small as possible, trying to get it as close as possible to the static pressure on the leading face.
From my first year in uni, it always fascinated me that turbulent boundary layers delay separation. To a bushy-eyed student, it's counter-intuitive.
Absolutely correct. The dimples "trip" the boundary layer airflow and cause it to "re-attach" a little further back which gives the overall result of delaying airflow separation from the ball's surface.
This results in a smaller area of pressure turbulence behind the golfball which in turn gives less drag. Less drag on the ball for a given amount of initial energy (the club hit) results in further distance flown.
Logan22L From , joined Dec 1969, posts, RR:
Reply 11, posted (10 years 3 months 2 weeks 2 days 9 hours ago) and read 2399 times:
Quoting Cptkrell (Reply 8): Although I am not proficient in golf ball aerodynamics, it appears that in Logan22L's snootiness, he also got the answer wrong
Quoting S12PPL (Reply 7): Why is a 41 year old being such an ass hole about a simple question?
Well, guys, I wasn't being an asshole as you say. In fact I have not professed to be an aeronautical engineer, but I posted a link that any chimpanzee could have found if they used Google. Does the term Google mean anything to you? Take your results from Google with a grain of salt, and try to be objective.
I think your responses would land you in hot water if you said these to your boss. All I was trying to say is: there are vehicles out there for this information, why do you have to post a thread here without doing the research first for yourself? Someday, you'll have jobs that require self-initiation. If you say to your boss "well, I have to consult A.net first," he might re-consider your employment.
Furthermore, my answer is not wrong. The dimples reduce drag, thereby increasing the lift produced by the golf club. They go hand in hand. Sorry if I didn't explain every last detail.`
"Would you respond the same way to a 5th grade class?"
No, never. Inquiring minds are subject to objective thought. I would nurture that; I would also encourage self-exploration and QA/QC. As far as I know, the thread poster is not a 5th-grader.
S12PPL From , joined Dec 1969, posts, RR:
Reply 12, posted (10 years 3 months 2 weeks 2 days 9 hours ago) and read 2395 times:
Quoting Logan22L (Reply 11): If you say to your boss "well, I have to consult A.net first," he might re-consider your employment.
Oh shut up. My God, listen to yourself! You are, in fact, being an ass hole about this. The fact that you can't just answer the question without being a sarcastic ass is proof of that! Guess what? People ask questions. Would you tell a 10 year old "Oh, sorry...You can't ask me why an airplane is able to fly. You need to go figure it out on the internet all by yourself."??? Would you tell a co-worker "Ya know...I think you need to go consult the company manual for that info. Even though I know the answer, I'm gonna be a dick head about it, and force you to find it for yourself. Cuz that promotes team work, huh???"
Get a clue. You could answer the question. But instead you choose to be an ass about it.
Logan22L From , joined Dec 1969, posts, RR:
Reply 13, posted (10 years 3 months 2 weeks 2 days 9 hours ago) and read 2387 times:
Quoting S12PPL (Reply 12): Oh shut up. My God, listen to yourself! You are, in fact, being an ass hole about this. The fact that you can't just answer the question without being a sarcastic ass is proof of that! Guess what? People ask questions. Would you tell a 10 year old "Oh, sorry...You can't ask me why an airplane is able to fly.
Nope. The thread-starter is 36-45. I think, in context, that my statements were really not so bad in light of some the the bull posted on this forum. That said, I guess I'm sorry, although I don't know why.
BTW, S12PPL, we had a great time in NYC. Glad you couldn't make it.
Bezoar From United States of America, joined Nov 2001, 807 posts, RR: 8
Reply 14, posted (10 years 3 months 2 weeks 2 days 9 hours ago) and read 2387 times:
So, why not put dimples on aircraft?
I suspect it has to do with the backwards rotation of the ball, with dimples being steadily presented from the underside effectively pushing it upward. If you put top-spin on a golf ball, it will dive quickly.
I think a golfball well hit with a driver will have enough back-spin to cause it to actually rise a bit, it's flight path a bit concave upward.
"There are none so blind as those who will not see."
Logan22L From , joined Dec 1969, posts, RR:
Reply 17, posted (10 years 3 months 2 weeks 2 days 9 hours ago) and read 2375 times:
Quoting S12PPL (Reply 15): Glad to see you are being the mature 41 year old you claim to be.
When did I ever claim that? You called me an asshole (I spell it correctly), and all I did was respond. I think you over-reacted. Hundreds of A.netters have said "why don't you Google it first?" I don't recall them getting persecuted as I have on this. I actually gave him an answer. Right or wrong, I took the time to look it up. That doesn't make me an "ass hole" just a guy who took the time to look it up, and comment that he could have done what I did, and saved us this whole bunch of bullshit.
A study was done on an aircraft, I can't remember when it was posted on a.net, but they basically put a rough skin on the wings. I assume it was supposed to give similar results as the golf ball scenario, but proved to not be cost effective.
Sidewinder From , joined Dec 1969, posts, RR:
Reply 19, posted (10 years 3 months 2 weeks 2 days 9 hours ago) and read 2373 times:
Quoting Logan22L (Reply 13): Nope. The thread-starter is 36-45. I think, in context, that my statements were really not so bad in light of some the the bull posted on this forum. That said, I guess I'm sorry, although I don't know why.
Yes I could have gone to google...but i like going to a.net because we all share something in common. I enjoy reading the posts (most of them) and getting viewpoints from other people.
Sidewinder - accept my apologies, please. I only meant to say that you can get this info on the internet, and sometime A.net is just not the most reliable source of information. You have to take any information that you get on the internet with a large grain of salt. That said, I really didn't mean to put you down. Several members can trash me here, but that is of no consequence. Welcome to A.net, and ask away. I trust I'll be the least offensive bastard you encounter over the next few months.
Now at the same time, there is a few of your threads that you could have used google on or expedia, but felt you needed to post on here and ask instead. That is the whole reason of having a non-av forum. Do you see some of the dumb things posted on here on a daily basis? If I do not like the thread, I do not post. Why waste your time, let someone else reply. The guy is new and he came here with a question, nothing wrong with the question.
Now I question I have, that I could not find an answer on google is, what causes me to spark a golf ball on contact? I use a Taylor Made 360Ti Driver that I had custom made for me. My average swing speed with a driver has been clocked at 97 mph. I tee the ball up high, and when I make perfect contact, you see sparks coming off of the clubface and ball.
Where did everybody go?
: Because aircraft aren't spheres. For spheres, the largest drag contribution is from the adverse pressure gradient caused by the wake. The dimples red
: Why do golf balls have dimples? It is called cellulite. It is common in people with high body fat and poor muscle tone - golfers for example. It is no