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Aerodynamics at the particle level

Found this paper while digging for more aero details, very recent too:
http://arxiv.org/pdf/nlin/0507032.pdf

I was specifically looking for something that discusses the actual particle behaviour, I couldn't quite get my head around the whole laminar and turbulent flow thing, everything just seemed to say it is one then magically becomes the other, but there was no phase change or anything like that, it just didn't wash with me.

This paper goes some way toward explaining some of these things,
overall written well and he does relate and explain a lot of everyday things and touches on some of the contradictions in fluid dynamics. Even though he has tried to simplify quite a bit, still very complex for a novice like myself.

Abstract below:

Quote:

Abstract
All aerodynamic forces on a surface are caused by collisions of fluid
particles with the surface. Upwash, downwash, lift, drag, the starting
vortex, the bow wave, and any other phenomena that would not occur
without the surface are caused by its presence as it interacts with the air
flow. While the standard approach to fluid dynamics, which is founded on
the fluid approximation," is effective in providing a means of calculating
a wide range of fluid behavior, it falters in its ability to account for the
effects of complex interactions of the fluid either with itself, other fluids,
or with solid bodies. One of the conditions required to justify the fluid
approximation is that the flow be steady[21], i.e. that the particles of the
fluid not be interacting with each other or with any surface. It is these
very interactions, however, that are the causes of aerodynamic effects on
solid bodies in the flow. This is not to say, of course, that the fluid
approximation is never useful, but that some well-known and important
effects such as the Coanda effect are not explained by that model.

Quote:

Originally Posted by Tesla (Post 354639)

Thanks. It takes me along time to get my head around it too. I have to read it over and over again :D. I'll print this off and have a read.

Fluid mechanics is so well understood that entire aircraft are designed numerically within a confidence of 2% as of around 2000.
If you want a good look at 'particles' I'd recommend a textbook and look at the section for submerged bodies in viscous flow.You should have at least a graduate level degree in mathematics.
For automotive work you'll need a super-computer and a fat wallet.After millions of dollars of CFD,automakers are still spending additional millions in the wind tunnel as a backup.

Quote:

Originally Posted by aerohead (Post 354994)

Just doing the best I can to satisfy this questioning mind.
But may I add to that,
in addition, after the wind tunnel there is rigorous road testing to prove the final design, and significant adjustments are often made then too.