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Physics, Astronomy & Cosmology / Laminar flow
« on: 04/12/2007 21:53:05 »
I'm gonna guess that the boundary layer is formed because air molecules stick in the imperfections in the wing/pipe wall and smooth it out. If the bumps and ridges were large enough the flow would turn turbulent because laminar flow would require large groups of molecules to 'stick' in the grooves which simply won't happen (on the small scale, EM forces can reduce the flow along the surface, but on a larger scale, these forces play less of a part in the behavior of the system). The boundary layer is kind of like wetting down a plastic slide. The water fills in the dips in the surface, reducing friction and allowing little kids to slide down it at high speeds.