Ah.. post #9. Started as witticism but then moved onto some serious stuff. I see, now.
Originally Posted by Dash&Thump
The answer IS Viscosity. Without that, you have a pointy land vehicle with wings.
A flat plate will fly because the viscosity allows it to generate asymetric airflow, the fundemental requirement to allow Mr Benoulli to do his bit.
The viscosity is the property that allows the air to seperate at the trailing edge and not come back up and join the other stream in the opposite place to the separation point at the front.
Still sounds a little like a circular argument: viscosity because then we can treat flat plate as if it were another Bernoulli object which requires viscosity.
So:
flat plate + viscosity => asymmetric flow => Bernoulli => lift
I must say that asymmetric flow is not the first think that I would expect from a flat plate but I guess my intuition developed without the help of hours spent in wind tunnel.
Again, a question arises:
flat plate + extremely low viscosity fluid => nearly symmetric flow => nearly no Bernoulli => nearly no lift ?
PS: Thick, I tell you! Thick is my head! 