When velocity is advected, is it anything like the draft effect in racing
Like I said, I'm not too fond of this idea myself. Imagine yourself observing a particular point in the ocean. You're trying to describe mathematically the changes in water velocity around you. A number of forces are at work. There's the pressure force, shear and stress forces, good ol' Coriolis...all those forces cause the velocity of the fluid around you to change. Now remember, for example, the eddies I mentioned above. They're localized "swirly bits" of ocean, and they can move around (kind of like a tornado but much less dramatic). If one moves toward you, it will bring along with it the velocity of the fluid in it. So the water where you're observing will suffer a change in velocity that's not due to any of the other forces I just mentioned, but just velocity that was "dragged in" from somewhere else. And a change in velocity is called acceleration. (Furthermore, wherever the eddy came from will have had velocity advected away from it.) So that's what I take to mean "advection of velocity". In our fluid equation there are, of course, mathematical terms to describe it!
