Yes, I did a search and you're probably thinking, wtf are hexagonal dimples. Think golf ball.
I know that unless you have an unlimited budget you can't modify your car exclusively with these dimples and i seem to remember the backing of some refrigerators have a sheet of aluminum that has similar dimpling. I want to conduct some experiments by blocking my grills or improving aerodynamics in some way with dimpled material, does anyone have a cheap source for this kind of material?
Oh yes, sorry, I have to explain my reasoning. Well (taken from
here)
Cylinders and spheres are very convenient and strong shapes when designing bicycle frames and components, but it turns out they are terribly un-aerodynamic. I know they look all smooth and round, how could the air not just flow right on by them? Part of what makes an object aerodynamic is the object’s ability to keep the air attached to the surface as long as possible. As soon as you have what is called flow separation from an object, drag increases. This is why deep rims and disk wheels are more aerodynamic, because the air stays on surface longer, and the flow separation takes place much further along the flow of that object. The same with those thick downtubes that almost all tri bikes have now. More surface area on certain parts of the frame mean less flow separation and improved aerodynamics.
It turns out that with a cylinder or sphere, that flow separation takes place very early as the air travels over the object. But, please dimples on that sphere, like a golf ball, and something changes. Those dimples increase turbulance, which normally you would want to eliminate in aerodynamic design. But this turbulence, or “dirty air” on a sphere has the effect that it actually speeds up the airflow and gives it more forward momentum. As a result, flow separation takes place much later in the flow over the sphere. Even though there is increased turbulence, the trade off is that the increased speeds in airflow has a net benefit on the aerodynamics of the sphere, and the air stays attached to the surface much longer.
It is also important to note this is why we don’t put dimples on just any shape or object for which we are trying to improve aerodynamics. If dimples improve aerodynamics on a ball, why don’t we dimple the wings of an airplane? Or make the bike frame itself dimpled? The reason is that those dimples increase turbulance, and on a wing or aerodynamically tapered bike frame, the flow separation is already fairly good. The net result of increasing turbulence on a shape that already has late flow separation is decreased aerodynamics, while the net aerodynamic result of turbulence on a sphere is positive, because the turbulence contributes towards delayed flow separation.
What would be the effects of aerodynamic dimpling on a car body? If a golf ball has a high CD on the trailing end then can dimpling decrease the cd of steep rear ends? Dimpling sports wear helped Lance Armstrong and the Japanese Women's Swim team, it helps reduce heat from high speed aircraft.. so, what exactly stops testing on cars? Again, anyone have an idea on cheap materials i can use to test with?