Quote Originally Posted by bennjamin View Post
this pipe will flow the same if not better than a totally smooth sided pipe of equal diameter. Think of the surface of a golf ball Anyway good work
I think it's a little more complex than comparing golf balls to internal airflow in a pipe. Golfballs have dimples so that its wake is alot smaller than if it had a smoother surface, this is because the boundary layer on a dimpled ball is turbulent and allows air to 'curve' around better.

If the piping was smooth, a smaller friction head would probably be calculated resulting in a lower velocity loss around the bends esp. of course it would be more expensive to buy custom smooth piping :P