[krytie75 (OP)]

From what I recall, the dimples on the surface of a golfball reduce drag on the ball and allow it to fly smoother and further than a completely smooth ball, from the same powered swing. I've also heard that coating an aircraft fuselage with dimples would have the same effect, but it's not practised because aircraft are so big that keeping the dimples clean is a logistical nightmare and the dimples would only be effective at one cruising speed.

This being the case, could a fan (of the pumping or cooling variety) exhibit improved efficiency or increased speed if the blades were carefully molded with golfball dimples?

I'm assuming not due to the fact that you can't get fan's with dimpled blades, but I thought it was an interesting question non the less.

krytie

[lightarrow]

Mmmh, it could be an idea. Remember however that laminar friction is just a small part of resistance in this case, because the motion of the blade has a component perpendicular to the blade's surface.

[krytie75 (OP)]

Aha yes I see your point.  It would be interesting to get a percentage breakdown of all the friction components on a stationary desk fan.  It feels like it should work, but I'm still not entirely convinced.

[SeanB]

There is a design where a blade has bumps added onto the leading edge, and this actually decreases drag and increases efficiency. have a google at humpback  whale fin and look at the bumpy whale fins entry, click the related link for more

[wolfekeeper]

Another similar idea I had once was shaping the fan blades to make them as similar as possible to an owl's wing. Owl's wings are very quiet, so it could significantly reduce noise.

[krytie75 (OP)]

Presumably a reduction in noise would be coupled with a marginal increase in efficiency.