Fluid friction redifined?

Have a look into

http://www.azom.com/news.asp?newsID=4922

Right time to split the forum into two.

1. Bumpy piping & fluid mechanics engineering forum
2. Smooth piping & fluid mechanics engineering forum

 

[jmw]

These scientists never played golf, did they?
They never saw a hull form with small steps in it either....

JMW

http://www.ViscoAnalyser.com

 

[rconner]

I think there have been several technical articles over many years concerning in effect beneficial effects of sort of specially designed surface roughnesses in various periodicals or journals (the word "ribulet" such as I see discussed at

http://ggcmedia.com/forum/posting.php?mode=quote&p=958&sid=9e8f01f4b60d45e9812aa59e50f33655

and probably many other sites sort of comes to mind, though this may be just one type of such deliberate efforts).

 

[m777182]

The skin of dolphins and sharks has been designed in accordance with the fluidodynamic inventions of science for last 200 million years... so open your eyes and learn from nature when walk arround.
m777182

 

[stanier]

In NSW Australia aeronautical developments are being used on vehicles to reduce drag. Simple metal winglets are fitted to edges of truck bodies. Fuel efficiency increases of 11% have been reported in trucks.

The theory is that the eddies create [revent the formation of drag and thus increase efficiency.

The degradation of eddies in slurries containing small quanitites of sand have been reported as reducing the friction at the boundary resulting in lower pressure drops. See work by Wilson Addie Clift & Thomas.

Uneven surfaces n the pipe wall is the reverse of this one could suppose.