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Richard Casady

On Sun, 17 Aug 2008 00:21:36 +0200, (Martin
Schöön) wrote:

"Glenn Ashmore" writes:

It has something to do with the texture and flexibility. It is apparently a
thick coating that has a microscopic surface pattern that slime spores and
barnacles have a hard time binding to. It also flexes slightly under
varying water pressure so the barnacle cement pops off. A side benefit is
that those little bumps improve laminar flow reducing wetted surface drag.
Sort of like the dimples on a golf ball.

It is the other way around actually. The dimples of golf balls are
there to trip the boundary layer to make sure you get rid of the
laminar boundary layer.

This is true.
When you hit a golf ball the loft [slope] of the clubface puts
backspin on the ball. This sucks air off the top and piles it up under
the ball. This pressure difference holds the ball up and makes it fly
farther. The dimples get a better grip on the air, so this Magnus
Effect works better. A smooth ball will go about half as far.

Casady