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-   -   engine simulation with mesh motion and topological changes (https://www.cfd-online.com/Forums/openfoam-solving/83177-engine-simulation-mesh-motion-topological-changes.html)

vangelis May 31, 2011 05:43

Hi there,

The "Output Sets" option was introduced
in ANSA v13.1.2, so if you have an earlier
version you will not see it.

I would recommend that you get the latest
one which is v13.1.3.

If you also want internal faces, you can indeed
create them with VOL-SHELL and then assign
them to a PID of type INTERNAL (you can do this
if you edit the PID card).

These elements will then be output in the faceZones
file. I believe you can then change this into a SET
using openfoam utility tools.

Best regards

Vangelis

abminternet May 31, 2011 06:33

Great thanks, you were right, I was using the wrong version :D now it works like a charm, it even writes the sets itself, no need to do zones to sets :D

vangelis May 31, 2011 07:02

you are welcome

abminternet May 31, 2011 18:19

Hey guys, so now that i can do sets, (thanks again vangelis :D ) it turns out I may be doing them wrong. The piston does not move, the cells that are supposed to move with the valve just get streched (only the points in contact with the valve top move), and the cells that are supposed to move and layered do nothing :S. So maybe I got it wrong. The pistonAuxPoints are the points that are supposed to move right? So that would be for example all 8 points of each cell in direct contact with the piston??
also, what is the cylinderSet, is it every other cell in the cylinder that does not contain those points? (that would mean the layer of cells just above the piston cells are not in the cylinderSet either?

and for the valves, staticPoints are the points belonging to the tetra cells above the hexas? and the movingInternalPoints, are they the points belonging to the hexa cells for layering? and the
movingPoints are then the lower tetra cells, the ones that move together with the valve?, and also the staticCells and movingCells, they correspond to the staticPoints and movingPoints i guess.

sorry that i ask so many questions, i just feel i am so close to making it work. Any help would be greatly appreciated

kind regards

abminternet June 1, 2011 08:33

hi everyone, so, after reading the code carefully, I have one question. Is the code even complete? It seems like it is not :S

Peter_600 June 9, 2011 09:00

Hi,

sorry I am a little bit busy at the moment. I ll come back to u the days with a small instruciton for the accordionEngineMesh class.
Could you post a figure of ur grid ?

thx
Peter

abminternet June 10, 2011 05:29

Hi Peter
 
No problem. My mesh looks like the picture. It is a simplified 2D mesh of my 3D case. I am using it for testing. The valve is not really tilted, but it is just a test, so I guess it should work just the same way, cause the axis and direction of the valve are specified. :) Well good luck with all the work, I guess I'll hear from you when you are a bit more relaxed.

abminternet June 10, 2011 05:30

1 Attachment(s)
forgot the pic, here it is

_DF_ August 17, 2011 10:58

Hi,

Is there sonicTurbDyMEngineFoam solver for OpenFOAM 2.0.1?

Paebin November 29, 2011 11:11

Hello everybody,

I have downloaded the simpleEngine case and it works great. It is a good example to understand the preparation of a dynamic mesh case in openFoam.

But in fact I'm more interested by the flow inside an injector than in a whole combustion chamber. I would like to move the injector needle, so I have to use a dynamic mesh. I don't need engineTime, I have no piston and my valve does not have a bottom, but my case is really similar to an engine valve (need sliding, layering and attach/detach). For that, and to start, I used the original linearValveLayersFvMesh class. But The attach/detach feature is not included in this class, so I have mixed linearValveLayersFvMesh and simpleEngineTopoFvMesh in order to add it.

I have tested my mesh with moveDynamicMesh and it works great. But with the interDyFoam multiphase solver, I have a problem with attach/detach, I got a "Floating point exception" during the first time step in both RANS (K-epsilon) and LES (oneEqEddy). If I switch off the turbulence in RANS or use laminar with attach/Detach, it works. If I use turbulence (RANS or LES) without attach/Detach (by removing all the faces in the "detachFaces" dict), it works too. I'm using 1.6-ext (updated last week).

My problem seems really similar to the one in the beginning of this thread but the simpleEngineStem case works on my computer, so the problem should be solved. Did anyone try to use attach/Detach with interDyFoam ?

Regards,
Fabien.

Abhishekd18 January 11, 2012 23:38

Seqmentation fault in engineTopoChangerMesh layerAR
 
Hi,

I am trying to run dieselEngineFoam_Scania case with layering. I have done the necessary changes in dieselEngineFoam solver and created dieselEngineDyMFoam solver. But I am getting segmentation fault in first time step. It seems that the solver enters mesh.update() and doesn't come out which is causing segmentation fault. Can anyone help on this problem?

My mesh is not the sector mesh. I have extruded it 360 deg full so I don't have cyclic boundaries.

kaparzo-shb January 27, 2012 21:31

HCCI geometry
 
Hi, every one,
please i need a engine 3d chamber gemetry for running un test of my film model. am working with Gambit and fluent.

Thanks.

Abhishekd18 February 10, 2012 04:57

dieselEngineFoam solver crashes in parallel at the start of injection
 
Hi,

I am running dieselEngineFoam in parallel on 4 processors. But as the spray injection starts the solver crashes. The setup runs perfectly fine in serial. I am using OpenFoam 1.6 ext. Can anyone help me on this?

Thanks.

Abhishekd18 February 15, 2012 07:10

Hi, everyone,

Does anyone know how openFoam maps fields while using layer Addition? I am using openfoam 1.6-ext dieselEngineFoam. The solver crashes (Floating point exception) when layer addition starts. Velocity magnitude is very high 7783 m/s and courant no. is also high. I think it is related to mapping fields after adding the layer.

Please reply if anyone knows anything about this.

Thanks.

deepsterblue February 15, 2012 08:44

Mapping fields for layer addition is meant to be relatively straightforward - All cells in the new layer are inflated from zero-volume.

Are you using adaptive time-stepping?

Abhishekd18 February 15, 2012 10:29

Yes. I am using adjustable Time Step. I am limiting max courant number to 0.1. But after layer addition it shows maxCo = 1.8 something.

deepsterblue February 15, 2012 10:35

You might want to manually print out the velocity field in the newly created cells (and face-fluxes phi for newly created faces) after the mesh-update to ensure that it looks reasonable.

Is this in parallel? If so, you might have to ensure that the partitioning is perpendicular to the motion-axis, since layer-addition / removal is known to be finicky there..

Abhishekd18 February 15, 2012 11:01

I have done manual decomposition which takes care of the direction of motion of piston, cyclic boundaries and layering. In fact, it runs perfectly fine when piston moves from BDC to TDC. The problem starts during expansion stroke when layering starts.

But the solution crashes after layer is added. I don't have even single time step after layer addition so that I can plot the velocity field.

deepsterblue February 15, 2012 11:05

That's because your runTime.write() is after your solution loop. Place it after the mesh.update() call, and you'll get the mapped field written out to disk.

You'll have to roll-up your sleeves and write some code for this.

Abhishekd18 February 15, 2012 11:18

Ok. I will do that.

What should I do after that?

What kind of code do I have to write?

And few more questions
1. When I modified dieselEngineFoam for layering, I did it as it is done in sonicTurbDyMFoam. But the solution diverges when layering starts. When I commented the statement "# include compressibleCorrectPhi.H" it runs perfectly fine. As far as I understood, compressibleCorrectPhi.H solves pressure correction after mesh change and it should be included.

2. While running in parallel, the solution crashed at the start of injection. When I started debugging the code, it turned out to be some problem with the statement "# include findInjectorCell.H" in sprayInject.C. Again on commenting the line, the solver runs and I can see the spary injected from the desired location.

What could be the reasons?


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