[aerohead]

Originally Posted by freebeard

I found interest in the Moody diagram and breakdown of CFD (DNS/LES/RANS)

Something fishy about this grid though.

Viscid/inviscid isn't black and white, it's a gradient.

The use of the word is contextual and dangerous if used loosely.
1) inviscid can describe an imaginary, frictionless fluid, incapable of supporting shear, or rotation, used in numerical models to establish streamline positions.
2) then the Bernoulli theorem is employed to establish the pressure distribution over the 'model' ,minus viscous effects.
3) then viscosity effects are incorporated to flesh out the total.
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4) inviscid is also used to describe actual, ' real' fluid, outside the boundary layer, which telegraphs pressure through the boundary layer to the lowest strata of air, adjacent to the surface of the model, measured as local static pressure.
5) all viscous effects are limited to the boundary layer.