Learning Forum

[Shiv1510]

Hi everyone, 

I am trying to simulate Stokes problem of Oscillating flat plate in turbulent regime. I have a 2D square domain, with left and right as periodic boundary conditions, top as symmetry and bottom as wall. The bottom wall is moved in sinusoidal motion using an UDF, starting from rest. My problem is that I want to use Transitional SST turbulence model (4 equation). 

The simulation works when I use any other turbulence model (k-epsilon, k-omega, Transitional k-kl-omega) but it does not work when I use Transitional SST model, instead it give me error: "Floating point exception" immediately when I start simulation. However it works if I give a constant velocity to the plate/wall. Can anyone help me as to how to fix the problem ?

[Rahul Kumar]

Hello, 

Can you please insert a picture of the mesh and the mesh details?

 

[Shiv1510]

Yes here it is

[Kalyan Goparaju]

Hello, 

Any particular reason you want to use the Transition SST model? The intermittency transition model is recommended over Transition SST. You can activate the intermittency transition model as a sub-model under K-omega SST turbulence model. 

Thanks,

Kalyan

[Shiv1510]

Yes, I want to, but after initialization it still gives me turbulent viscosity limited to viscosity ratio 1.000000e+05 in 5922 cells. How do I solve that ?

[Rahul Kumar]

Hello, 

Can you reduce the relaxation factor for the turbulence parameters and try again? Thanks! 

[Shiv1510]

Hello Rahul,

Apologies for replying late, I tried reducing "Intermittency, Turbulent kinetic energy, dissipation function, and turbulent viscosity " but it still giving me same problem. Just to be sure, we are talking about "under relaxation factors" right ? I reduced their values by different factors but no change.