Golf Ball Aerodynamics

[BreezyRacer]

[/quote]That sounds like you are describing riblets. 3M researched with riblets which were parallel to the flow. They reduced drag by about 3-7%, but have yet to be implemented because fuel prices aren't THAT high yet.

Studies have been conducted on dolphins, because in theory, they shouldn't be able to swim as fast as they actually can, until they looked closely at the skin and noticed strange patterns; riblets. Barracuda's release polymers along their skin that reduces drag by as much as 40%

Sorry I started to go off at a tanget [/quote]

On the contrary, not a tangent at all. Whatever the means the goals are pretty much the same .. to break down boundary layers and energize the air so that it can conform to surface changes. They're all a form of vertex generators, designed to trip up the airflow right at the surface. If others want to see practical application of vortex generators search for Mitsubishi and vortex generator. Doing so will pull up a very interesting paper on VG's for the roof line of the Evo. In the future we'll see more VG's.

In F1 there is a lot of VG development in the barge board area, with sawtooths and winglets. Speaking of winglets has anyone spied the winglets buried in the front wing of the new Toyota? I suspect that they are to produce a vortex aimed at the brake ducts, but that's just speculation.

[Cornell Racer#1]

The dimples are for reducing the turbulence wakes, which occur during flight of the ball! By doing this, you can get a better accuracy....

[Ciro Pabón]

The dimples are for reducing the turbulence wakes, which occur during flight of the ball! By doing this, you can get a better accuracy....

Is't this just a side-effect? As Manchild points out, Tomba said:

well, the following as true about the dimples in a golfball: "a turbulent boundary layer can better follow the curvature of the ball's profile. It travels farther around the ball before separating, which creates a much smaller wake, and much less drag. In fact, a dimpled golf ball has only about half the drag of a smooth one."

Besides, I read in NickT link:

In 1845, the gutta-percha ball was introduced. This ball was made from the gum of the Malaysian Sapodilla tree. This gum was heated and molded into a sphere. This resulted in a very smooth surface. The typical drive with the gutta-percha ball was shorter than that obtained with the "featherie". However, according to golf legend a professor at Saint Andrews University in Scotland soon discovered that the ball flew farther if the surface was scored or marked.

[Cornell Racer#1]

It smooths out the flow over the shape and gives it more lift as well. I got a picture of a golf ball in the windtunnel, which I did for a lab in school. I would post the picture if I figure out just how?

[Ciro Pabón]

Put the photo adress between the tags [img]and[/img] or highlight the adress and click on the "Img" button on the "Post a reply" window. If the photo is in your PC register in http://www.googlepages.com or click on "Photo sharing" in http://www.imageshack.com to get an account and upload the photos to a public adress.

Sorry to insist, but it is an increase in lift or a reduction in drag what takes further the ball?

[Cornell Racer#1]

Due to Lift, the ball will rise higher and have greater trajectory.....I am not sure if you've seen a flow around a "Cylinder" but, the "spots" on the golfball are there also to create low pressure on the top and high pressure on the bottom. And this happens because the ball is rotating on its axis while moving forward! The high pressure on bottom pushes the ball upward giving lift....

Delta WING....




20Degrees....


2 Degrees..... with VonCarman Vortices trailing in the back....


Gives you SOME idea....


Here's a link to what I am talking about moving and spinning balls!!!
http://www.grc.nasa.gov/WWW/K-12/airplane/cyl.html Just use the "Cursor" to increase the rotating angle and see how the flow changes creating high pressure on the bottom.... When those to "White" lines meet than theoretically lots of weird stuff happens but, i won't get into that and bore you with....

[syguy]

Dimples on golf balls and vortex generators on wings are both designed to induce turbulence in the boundary layer.

Find out why

However, riblets appear to delay laminar to turbulent transition within the boundary layer.

I'm guessing that you don't see these types of surface treatments on F1 cars because they don't help. Typically all these techniques of reducing drag are sensitive to a 'cruise' condition and alignment with the on coming air. Given the wide variation in speed of an F1 car around a circuit these techniques are unlikely to offer an overall advantage.

Also given that the size of these surface treatments are small they would be difficult to scale down further to wind tunnel model sizes. Also CFD would struggle to resolve such small features and would have even more trouble predicting laminar to turbulent transitions.