Boundary conditions: inlet and outlet
Does anyone know where I can find how to use the boundary conditions?
I've looked at the user guide which tells me that a range of BCs are available at src/finiteVolume/fields/fvPatchFields/derived. But I don't know how to use them. I don't understand what goes with what (for example, a specific BC goes with mixed or calculated?).
I'm studying a flow with an inlet (with a definite velocity) and an outlet. I don't know which BC I have to put for these 2 surfaces (inlet and outlet). As there is no gravity in my problem, I guess I should take a BC which fixes the pressure to zero for the outlet, but I don't know which one.
Could anyone help me? thanks a lot in advance.
For the velocity, you can put:
So what happens when you switch to turbulent? Can you keep the same boundary fields??
I have the same question : are you sure it works only in a laminar case, one told me to use such conditions in my turbulent case.
If it does not work in a turbulent case, do you know what kind of boudnary conditions would work so ?
PS : Finally those conditions did not work in my DNS case, it gives me a field without any variation ... Help ^^
using outlet velocity profile as inlet
Does anyone know how to specify (in COMSOL) an inlet velocity profile from a previously solved model's outlet velocity profile?
I've been trying to create a Fourier Series representation of the profile over time, but I am having trouble doing this with a space and time dimension together.
Any help greatly appreciated. Thank you!
To “using outlet velocity profile as inlet”
1. in constant/polyMesh/boundary
offset (0 0 1); // offset (0 0 1) is the distance between the inlet and the outlet
2. in 0/U
value (0 0 0);
average (0 0 2);
Then you can check whether you want results.
problem with boundary
I also have problems on defining the bounary. For pressure, when using zeroGradient for inlet, everything goes well. After changing zeroGradient to calculated, I get this message:
valueInternalCoeffs cannot be called for a calculatedFvPatchField
on patch inlet of field p in file "/home/flow/OpenFOAM/flow-1.6/run/pipe/tphase/ke/0/p"
You are probably trying to solve for a field with a default boundary condition.
From function calculatedFvPatchField<Type>::valueInternalCoeffs( const tmp<scalarField>&) const
in file fields/fvPatchFields/basic/calculated/calculatedFvPatchField.C at line 145.
can anyone tell us how to use the boundary conditions?
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