Originally Posted by deniggo (Post 287652)

Hello,

I would like to use groovyBC for a periodic inlet/outlet. I tried the tutorial 4.2.3 on http://openfoamwiki.net/index.php/Contrib_groovyBC. In 0/U phi is taken into account and not U directly. So, I modified the BC to:

But this error occurs: The expected return type vector is different from the stored result type "tensor".
I guess there's something wrong concerning the definition of U=vector and phi.

What do I have to change to get the bc running?

Thanks for your help,

Nico

Originally Posted by nimasam (Post 288061)

groovyBC+cyclic patch
hi foamer
i have used groovy BC as cyclic patch but i encounter following warning :

FOAM Warning :
From function PatchResult::getUniformInternal(const label size,bool noWarn)
in file PatchResultI.H at line 96
The minimum value -30172 and the maximum 10751.6 differ. I will use the average -22562.9
any one knows whats the problem here :( ?

i have an axiymetric tube with one inlet and one outlet as pressure and tempreture are not cyclic
i cant use cyclic boundary condition, another suggestion was direct map boundary condition but it was useless too!!!
any suggestion? i want something that work exactly like cyclic boundary condition but i also can change boundary condition for T too?

P.S.

inlet ----------------------------outlet

---------------------------------------
BC :
U,alpha are cyclic
P are cyclic with pressure jump (pressure gradient is fixed)
(dT/dx)inlet = -(dT/dx)outlet

Originally Posted by nimasam (Post 288217)

hi bernard
as my input and output face and cell are the same i only want a direct map of out let into inlet for u and alpha as the first step;) so i did:
inlet
{
type groovyBC;
variables "alphaOutlet@outlet=alpha1;";
valueExpression "alphaOutlet";
value $internalField;

}

outlet
{
type zeroGradient;
}
but i encounter previous warning, is not possible to do this action with groovyBC?

Originally Posted by latvietis (Post 359747)

I have a question about this warning.

What does it actually warn me about?

Where this minimum and maximum value can be found and from where it actually is calculated?

BC looks like this:

Originally Posted by latvietis (Post 362061)

Problem is that there is no simple tutorial how to do this and my skills are so low...

How this groovyBCJump is working? Any example for this?

Originally Posted by mcdonalds (Post 413245)

Hi Bernhard,

I looked at some documentation on groovybcjump and it may be what I need. It says this:
Now let's say I want to make the value of both cyclic boundaries zero. What would I need to put into the boundaryfile folder?

Right now I have this:

Sincerely,

Benjamin

Originally Posted by gschaider (Post 413253)

Jump means that if one side has the value p1 and you specify a jump deltaP then the other side will have a value p2=p1+deltaT. Seeting the jump value to 0 should give you p1==p2

Originally Posted by mcdonalds (Post 413262)

Ok, that makes sense．　What if I wanted to make a zero flux on both cyclic boundary patches. Anyway to do that? Also, when I assign cyclic am I restricted to only using groovyBCjump or can I use the plethora of groovybc types, including groovybc itself?

Originally Posted by gschaider (Post 413465)

The reason why you're not making them walls is because all other quantities should be transported across in a "cyclic" way? Problem is that if the patch is cyclic you can't set a "fixedValue" there. Would have to play around with it myself, but I think one way to go would be to make the patches "mapped", set U with fixedValue and "transport" the other stuff by using the mapped functionality

Originally Posted by mcdonalds (Post 415373)

Hi Bernhard,

So I was able to map patches for one field doing what you said and create a fixedValue for another field. Good news is I am getting the same results as when I used groovyBC, and without the warning message to boot. Bad news is is that they are still incorrect results. What I should be getting is a linear curve (I run plot over line in paraview on the y-axis and just look at my H2O scalarField), but I get linear up to my boundary and then parabolic afterwards. Is there anyway I can get linear throughout the whole domain, like it should be? (Actually if you look at H2 it has a linear result, as it should)

I have attached my case file and my solver. They are very basic. I just run blockMesh, waterFoam2 and paraFoam to view it.

Hopefully, you can take a quick look to see if is possible to get a linear curve.

Originally Posted by mcdonalds (Post 417057)

Hi Bernhard,

I have a two real quick questions about openfoam.

Originally Posted by mcdonalds (Post 417057)

1) I'd like to create a variable, let's say D and make it a function of y. So something like D=5y+6. Is this possible in openFoam?

Originally Posted by mcdonalds (Post 417057)

2) I'd like to integrate over a length in the y-direction. I was going to put my field (let's say jbv) in my time step and use the += function to sum up. However, I would have to also multiply by the size of the cell along the y-direction at each time step (They are uniform in my model). Do you know how to reference the length of the cell in the y-direction?

It would look something like this: P += jbv*dy (where dy is the length of the cell in the y-direction)

Originally Posted by gschaider (Post 413253)

Jump means that if one side has the value p1 and you specify a jump deltaP then the other side will have a value p2=p1+deltaT. Seeting the jump value to 0 should give you p1==p2

Originally Posted by cheng1988sjtu (Post 512651)

I see the example case in Example/tests/jumpChannel/ in the release of swak4Foam.

I tried to understand how they define the pressure jump, because in the example files, they define two jumps, jump1 and jump2 by the following lines:



and they define two different jumps in the 0 files.

So this means that each jump (jump1 and jump2) defines two faces with a pressure difference on the faces, but how do they define the two faces by simply one line, for example, for jump1:



Now, after I get to understand how to use groovyBCJump, What if I want to define a pressure jump between inlet and outlet? In my case, the inlet and outlet are cyclic, but I want to define a pressure difference between these two faces.

My domain size is (0 0 -0.001) to (0.22 0.3 0.001)

so should I define the jump faces as:



But after I do this, I'll get the following information:




This means that I defined 0 faces as a result!!! But Why??? If somebody can help me to understand this, I will really appreciate them!!!