Dear All, during the Fluent iteration, I got the message of" turbulent viscosity limited to viscosity ratio of 1.000000e+005 in 211 cells". Who can give me some advice of that? Thanks! Jason

Dear Jason,

Give few details about your case.

Generally lower down your urfs, solve flow first and then turbulence, change turbulence model from std to RNG...

Check your mesh quality

Dear DEV,

thanks for you kindly help. I found most of the cells that over the turbulent viscosity limited are local in the inlet. my simulation is just about the flow in some simple air path. I use the mass flow inlet. Isn't the mass flow inlet boundary will cause this problem?

check your mesh quality, make sure the Y+ value matches to the tuburlent model and near-wall treatment. you can refer to this website: http://geolab.larc.nasa.gov/APPS/YPlus/

Other way is go to control-limits, change the value(increase) of turbulent viscosity.

hi,

there may 3 main reasons for that.

1.bad quality mesh.

2.improper boundary condition for turbulence

3.improper turbulence model..

check your qty,relax urf,if u solve for second order solve for first order then switch to second order.... use simple turbulence models for inital iteration then go for higher models...many times reducing the value of TI% for some iteration will work.