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Old   July 3, 2014, 04:36
Default Sliding interface- ACMI
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Felix
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Hello
I'm working with OpenFOAM to study the behaviour of automatic valves in reciprocating compressors.
The first problem encountered is the interface beetween two non conformal and non-overlap mesh ( lateral cylinder surface and pocket valve ), the first is dynamic mesh, the second is fixed. Each non-overlap zone is wall.
I'm using,as a starting point, oscillating2DACMI modified with rhoPimpleDyMfoam.
I have the problem with overlap zone.
You can see that with the 3 pictures attached.

thanks a lot

Fely
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Old   July 15, 2014, 05:54
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I solved it using GGI interface with foam-extend version.
Now the problem is: how to define walls for non-overlap face?
And how to simulate in parallel if I have more than 1 couple of GGI interfaces.
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Old   September 11, 2014, 10:09
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Quote:
Originally Posted by Lesson View Post
I solved it using GGI interface with foam-extend version.
Now the problem is: how to define walls for non-overlap face?
And how to simulate in parallel if I have more than 1 couple of GGI interfaces.
Hi Lesson
You wrote that you solved your problem with use rhoPimpleDyMFoam and GGI?
Can you tell me how did you do that?
best regards
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Old   September 13, 2014, 17:31
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I think it can be done using AMI in OpenFOAM 2.3.
Its all about defining cellZones and cyclic boundaries.
You obviously must have two regions, each region must be defined as a cellZone so we can use it later in dynamicMeshDict.

After that in dynamicMeshDict you can use,

Code:
dynamicFvMesh   solidBodyMotionFvMesh;

motionSolverLibs ( "libfvMotionSolvers.so" );

solidBodyMotionFvMeshCoeffs
{
    cellZone        cellZoneName; //Change to your cellZone name.

    solidBodyMotionFunction  oscillatingLinearMotion; //Use any motion you desire
    oscillatingLinearMotionCoeffs
    {
        omega           1;
    amplitude    (0 1 0);
    }
}
I hope it helps a bit,
Best.
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Old   September 16, 2014, 11:53
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Hi Mojtaba.a,
Yes I set up my case in the OF2.3 with AMI.
However my case runs only if I use lowWeightCorrection 0.2
After 0.2 s solver crashes. I wanted to make rhoPimpleDyMFoam in OpenFOAM extended 3.0 but I cannot. I do not know how to solve my problem.
best regards
Przemek
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Old   September 16, 2014, 15:27
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Quote:
Originally Posted by gaza View Post
Hi Mojtaba.a,
Yes I set up my case in the OF2.3 with AMI.
However my case runs only if I use lowWeightCorrection 0.2
After 0.2 s solver crashes. I wanted to make rhoPimpleDyMFoam in OpenFOAM extended 3.0 but I cannot. I do not know how to solve my problem.
best regards
Przemek
Well does mesh deforms while running? because it shouldn't since you use ACMI.
First try testing your mesh movement with "moveDynamicMesh" to make sure everything is fine and then start simulation using rhoPimpleDyMFoam.
Tell me what happens when you run moveDynamicMesh.
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Old   September 17, 2014, 23:12
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Quote:
Originally Posted by Mojtaba.a View Post
Well does mesh deforms while running? because it shouldn't since you use ACMI.
First try testing your mesh movement with "moveDynamicMesh" to make sure everything is fine and then start simulation using rhoPimpleDyMFoam.
Tell me what happens when you run moveDynamicMesh.

Hi Mojtaba:

From your earlier post, it appears you are suggesting that its not possible to use ACMI with deformable meshes i.e. when the dynamic mesh is not a solid body motion. Do you by chance have any idea how sliding interface with deformable mesh motion can be implemented either in OF or the extended version?

Thanks.
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Old   September 18, 2014, 03:44
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Quote:
Originally Posted by ovie View Post
Hi Mojtaba:

From your earlier post, it appears you are suggesting that its not possible to use ACMI with deformable meshes i.e. when the dynamic mesh is not a solid body motion. Do you by chance have any idea how sliding interface with deformable mesh motion can be implemented either in OF or the extended version?

Thanks.
Dear Ovie,
I am afraid I cannot help you on this, but just for curiosity does your case really needs both methods at once to be solved?
For typical problems just one of them would suffice.

Best.
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Old   September 18, 2014, 14:13
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Thanks for your response.

Quote:
Originally Posted by Mojtaba.a View Post
Dear Ovie,
but just for curiosity does your case really needs both methods at once to be solved?
Frankly I dont know at the moment, but let me break it down to see if you can provide any insight.

The problem I am trying to simulate involves two concentric cylinders : a smaller diameter cylinder (SDC) initially positioned at the top of a second larger diameter cylinder (LDC).

The top surface of SDC is a piston that moves up and down to compress or expand the air inside SDC.

SDC is initially empty while LDC contains liquid up to some some level.

At time > 0; SCD slides into LDC and as it slides down, the piston surface simultaneously moves upwards to create suction pressure inside SDC so as to aspirate liquid from LDC into SDC.

After aspirating a certain volume of liquid, SDC starts moving upwards while piston surface at the same time moves downwards to create pressure for expelling aspirated liquid from SDC into LDC.

This cycle is repeated multiple times.

So there is the problem I am trying to simulate. Do you have any pointers on how to use the current capabilities of OF/extend to model this?

Thanks again for your time.
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Old   September 19, 2014, 03:34
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Well it is a little bit hard to imagine, two further questions,

1. Does your problem includes two phase?
2. Is bottom surface of SDC always open?

Maybe you can provide a simple sketch for better insight?

Best.
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Old   September 22, 2014, 09:19
Default ggi interface
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Hi everyone
Sorry for my late reply
i tried to solve my problems with OF 2.3 ( ACMI )
This kind of solution is not good for body that have sliding interface and deformation mesh ( maybe It's better to say that I'm not able to do it with ACMI ).
So I started playing with OpenFOAM extend -version . The great advantage of this release is the GGI interfaces. You can manage two separate bodies with all kinds of mesh motion. The disadvantage is that you can't put no slip condition for wall in non-overlap interfaces.
The second disadvantage is that in OpenFOAM-exetend version there isn't rhoPimpleDyMFoam implemented, you have to build it.
There is a tutorial: mixerggi, that explain you how to setup the case with GGI interface.

Bye
Fely
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Old   November 17, 2014, 16:52
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Hi lesson
I hope a good night for you!

I am simulating a valve motion like you but in a pipe. I used ACMI and I have a problem like yours. Also I used GGI in extend version of 1.6 that by moving the valve down the until after some time the negative cell volume occur and the non-overlap patches can not be considered as wall. Have you solved your problem?
If yes can you adise me in this regards?
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