Oscillating inlet BC
I am trying to set up a 3D case for an oscillatory flow past a circular cylinder. I'm wondering how would you specify the inlet and outlet BC for this easy case? It got me stuck here...
For the inlet boundary condition, I want to have Ui=Um*sin(2*pi*frequency*t), so i have set "patch" in /constant/boundary file for the inlet (for the top and bottom boundaries, which are perpendicular to the cylinder span, i have set "cyclic" BC for infinite length cylinder), and in /0/u file i have :
refValue (0 0 0);
value uniform 0;
But when I run it, the following error msg appears:
--> FOAM FATAL ERROR:
gradientInternalCoeffs cannot be called for a calculatedFvPatchField
on patch inlet of field p in file "/home/kyang/OpenFOAM/OpenFOAM-2.1.0/icoFoam-t/3DCylinder/0/p"
You are probably trying to solve for a field with a default boundary condition.
From function calculatedFvPatchField<Type>::gradientInternalCoef fs() const
in file fields/fvPatchFields/basic/calculated/calculatedFvPatchField.C at line 186.
Seems like it is complaining that I didnt define p, but as I said, I did subscribe inlet BC for p in 0 folder! :confused::confused::confused:
I'm just wondering if any one has any ideas on what's the problem for this... or any suggestions on the setup for BC and initial condition for oscillatory flow past a circular cylinder would also be great!
Thanks a lot!
Why have you set to "cyclic" your boundary ?
oscillatingFixedValue work with patch type.
And for pressure, use outletInlet or zerogradient.
in the boundary fle you can have primitive BCS : cyclic(AMI),symmetryPlane, patch, wall
inlets and outlets are type "patch" in the boudary file
in the variable files you may set specific stuff like the one you did:
but the primitive bcs in the boundary file gotta be "patch"
check the user guide.. it has more to it :)
First really thank you for your reply!
Second sorry it was a typo,,, I didn't use cyclic in inlet and outlet, I did use patch, I have changed that typo in my post... sorry about the confusing...
then, my problem is, how would you specify the condition for initial p in 0/p after setting 0/u at inlet to be oscillatingfixedvalue? According to NS, once you have u=Um*sin(2*pi*f*t) then at inlet you ought to have partial(p)/partial(x)=-partial(u)/partial(t)=-Um*2*pi*f*cos(2*pi*f*t). Basically p should be calculated according to u... therefore I have set 0/p to be calculated at first, but then the error like I described in my post appeared...
And I tried to use zeroGradient, however i got all values of p and u at all timesteps to be 0 following that specification. Here's what I did:
In my input file for boundary:
inlet type is set to be patch
and then in 0/p,
inlet type is set to be zeroGradient;
in 0/u, if i want to specify U=Um*sin(2*pi*f*t),would the following be correct?
refValue uniform (0 0 0); //steady current velocity, which is 0 in my case
//offset (0 -1 0);
amplitude constant 1; //Um
frequency constant 0.5; //f
//value uniform (0 0 0); //not sure what this is for?
Could you tell me my problem, really appreciated.
Thank you for your suggestion.
I tried outletInlet for 0/p at inlet as following:
And I still got all 0 values for p and u at all timesteps....
I begin to wonder if I should specify inletOutlet at outlet for U and p too? In my current settings I just used zeroGradient for u at outlet and p=0 at outlet. This looks less scientific now... should I change it to inletOutlet then?
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