[elmo555]

Dear Foamers,

I'm trying to set up an external aerodynamics simulation with the k-omega-SST turbulence model, and I'm wondering which values to choose for the k and omega fields.

There are various descriptions online on how to calculate the boundary conditions, e.g.:
Wiki: Turbulence free-stream boundary conditions
iChrome TURBULENCE CALCULATOR
Spalart: Effective Inflow Conditions for Turbulence Models in Aerodynamic Calculations

All of the formulas proposed lead to similar values for my simulation setup (air, U=20m/s, turbulent intensity at inflow I=1%, ref. length L=4.5m, turb. length scale=0.05) of



With these values, the turbulent viscosity nut in the free stream will be 0.06, since nut=k/omega, but the calculated nut value near walls is much lower, resulting in a really strange-looking flow field, similar to what's shown in the attached screenshot.

If I increase the omega value to a much higher number, the field looks OK, but this shouldn't be the approach to fix problems.

Can someone help me with these boundary conditions? Any tips are appreciated!