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-   -   Form vs. Friction drag (http://www.cfd-online.com/Forums/main/4511-form-vs-friction-drag.html)

Chris Stephens March 8, 2002 09:52

Form vs. Friction drag
 
The current regulation on boat roughness means that you can't put excessive roughness on the hull of a racing boat, similar to the dimpling used on golf balls, however should the hull be as rough as possible, i.e. should we leave it slightly rough or polish it to a smooth finish?

The dimensions of the boat are 30 foot long, and the profile is about 6 foot.

Pete March 8, 2002 15:02

Re: Form vs. Friction drag
 
In the case of the golf ball, the dimples trip turbulence, thus delaying flow separation and reducing form drag. Friction drag goes up but the benefit in pressure distribution more than offsets this.

In the case of a ship, I would expect no separation until the stern in reached, correct? Therefore the key driver one has control over would be the friction drag, and one would want a smooth surface to maintain laminar flow as far as possible, no?

I'm no sailor but there's my $0.02.

Chris stephens March 16, 2002 09:06

Thanks
 
Thanks


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