general question about wall distance in ICEM + CFX

Andy

Hello,

I am wondering about the wall distance that is achieved by using the prism-mesher in ICEM.

The manual is telling that when boundary layer seperation from a smooth surface is supposed to be simulated there has to be a wall distance of the first node of 'Y+'<2. Therefore an equation is given that gives an idea what initial height for the first prism layer (or the first variable node?) should be selected in order to achieve this Y+. (Eq.20 in 'Guidelines for Mesh Generation')

My question is: When using CFX the finite volume approach is used and hence the flow variables are finally calculated at the centres of the cells,right? If that is the case then when setting the initial HEIGHT of the first prism layer I am actually setting up DOUBLE the distance of the required height? Is this fact already incorporated into the Eq.20 that means does the ICEM-manual account for a finite volume approach that is taking the mesh nodes as the FV-vertices and not as the FV-center?

I hope that this has not been to confusing and some pro out there is able to answer those questions... ;-)

Thanks anyway, Andy