Hi Everyone,

I have been trying to understand the mechanics of the wall function approach used by CFX.

I've calculated y+ and u+ for a selection of points next to a wall. I expected the plot (y+ versus u+) to show a straight line as defined by the log law (y+ > 11.06). Instead there is a fair bit of scatter around the line.

Is there anything obvious I'm missing?

For reference: y+ = [delta y * (shear stress / density)^0.5] / kinematic viscosity u+ = velocity / (shear stress / density)

Any help much appreciated

Paul

With CFX4, Tascflow or CFX5 ?

I'm using CFX 5.7

Paul