Help regarding field functions in star CCM+
 

Hi,
Firstly I'm new to Star CCM+ and CFD simulations in general. Now to the question.

I'm currently trying to plot the turbulent boundary layer profile as a function of the wall y+ value. The general thought is to illustrate the relevance of high y+ wall treatment for coarse meshes and low y+ wall treatment for fine meshes. However, when I try to create a field function reflecting the turbulent boundary layer velocity given by the formula "u_tau = sqrt(tau_w / rho)", then I get the following message of error:

Error: function 'Simulation>FieldFunctionManager>UserFieldFunction ("TurbBoundaryLayer_Velocity")' compilation error: syntax error
Unable to compile expression "mag($${Velocity})/(sqrt(mag($${WallShearStress})/${Density})"

I think the problem might be an incorrect use of the "mag" tool, but maybe one smarter than me knows how correct this. :)

Thank you for your attention.
Rasmus.

Hello!

I don't know if you are still looking for an answer but you are missing a closing bracket in the denominator.