DaySailer.org Forum

I've been puzzling over how a centerboard or rudder produces lift.

I thought I understood how an airplane wing produces lift, with its asymmetrical shape, but according to the Wikipedia entry, even that's not correct (maybe).

I'm utterly baffled as to how a symmetrically-shaped foil can produce lift in the desired direction. Or maybe I don't understand the definition of lift correctly.

Anybody know, or know of a helpful link?

Anybodyof a helpful link?

http://www.arvelgentry.com

That website describes mostly the aeraodymics of sails, however, aerodynamics and hydrodynamics are essentially the same discipline, just with different parameters for the medium (density, viscosity, etc).

The reason he gives is that boundary effects (in air) and viscosity (in water) are the primary effects that destroy the symmetry.

If you look for his discussion around Figure 1 in his paper The application of Computations Fluid Dynamics to Sails I'm sure you'll find that a good starting point.

Thanks for the link, GreenLake. It's pretty thorough.

I'm beginning to think there's a reason that a lot of sailors are engineers, and vice versa.

Yep.