[Elgadari]

Hello Guys
I am simulating VAWT in wind tunnel and I have a question about boundary conditions
I set turbulent intensity and length scale for inlet and outlet equally
which are 0.1% and 0.005m respectively
Is this correct

[bpulat]

Hey Elgadari,
How did you set Turbulence Intensity and Length Scale for the outlet ?
Their purpose is to determine how flow will react from inlet to outlet in the selected Turbulence model.

[Elgadari]

hi
you can do it like that
go to Boundary conditions> Outlet
and you find it there.
Do you think that I suppose to keep default values for the outlet?
I am not sure. could you please share your experience with me

[bpulat]

I do know where to find the Backflow Turbulence intensity and length scale.
The thing with backflow parameters are that they are taken account by Fluent if any backflow occurs during iterations.
I don't see any backflows happening in well built wind tunnel simulation but if there is a backflow in your application you should first determine direction of the backflow.
In my experience lowering the values of the outlet turbulence parameters helped convergence, incase of some backflows in the early iterations of the solution.

[Elgadari]

hi
please refer to the attached screen shot, just taken from my laptop.
and you find how I set the outlet boundary conditions
Another question
Are you simulating VAWT also?
If so we may can help each others. since we still learning.

[bpulat]

I set turbulent intensity and length scale for inlet and outlet equally
which are 0.1% and 0.005m respectively

Intensity is set 1 % not 0.1 and length scale to 0.05 m.
Other than that everything is fine on the outlet parameters.
But from oscillations in your residual graph, something is not right.
How is your geometry and meshing ?
I am not simulating VAWT specifically, i work on varius external flow applications.