[ADGlassby]

Hi everyone, I'm having real problems getting a 2D moving mesh to work using SnappyHexMesh. I have looked though various examples of either 2D or moving mesh (using AMI) but I don't seem to be able to make the connection between the two concepts.

My mesh is (very basically at the moment) a circular (cylindrical) boundary with a rotor at the centre. I can create the basic geometry using snappyHexMesh to get the cylindrical mesh with the central rotor and it looks pretty good. I have used the sHM (castellatedMesh only run), flattenMesh, extrudeMesh, sHM (Snap only run). This produces a really good quality mesh. If I try to introduce the AMI interface, following the AMI (3D) examples, using an STL geometry file as the AMI location. This all disappears when I carry out the extrude step so the whole process fails.

I think I'm failing to understand the construction of the AMI interface. My understanding is that the AMI interface is made up of (in my case a circular rotating zone) a fixed FaceZone facing onto a moving (rotating) CellZone in which the rotor should be embedded. The rotor wall should be set up as a nonMovingWall which then causes it to rotate at the speed of the rotating mesh. The rotating cellZone slides past the faceZone and is allowed to do this because of the mesh construction and the declaration of cyclcAMI in the BC files and other relevant locations.

I have attached a basic picture of my geometry. Note that I am using sHM because the geometry I have in mind is a little more complex than the jpg I have attached.

If this is right.... How can I do this AFTER snappyHexMesh has developed the basic mesh?

I could REALLY do with some help now, does anyone have experience with 2D moving meshes (AMI style) using sHM??

Your help would be greatly appreciated. I have been going round in circles now with this for over a month and my head is beginning to spin. I'm sure this isn't as hard as I'm finding it!!

Best Regards

Andrew

[ADGlassby]

I have tried the following.... Instead of using a tube as the AMI interface STL geometry I have used a 3 dimensional Cylinder Primitive in my CAD application and then exported this as an STL file with vertical extent the same as my background mesh. I had noticed that the refinement stage in snappyHexMesh was complaining about the geometry not being closed. This hasn't improved the failure , however looking at the log file for sHM I have noticed that during the snap phase (morphing stage) there are no baffles created for the AMI zone which I find a little puzzling because baffles are created in the new annularThermalMixer tutorial.

Not sure what to make of this but I think this could be a pointer to the problem??

Andrew

[ADGlassby]

Sorry to keep posting.... when I try to run the solver (pimpleDymFOAM) I see that the rotor turns, which to me means that the rotatingZone has been recognised. But the AMI interface stretches rather than slides. This causes the solver to crash, obviously. so perhaps sHM is creating the cellZone but not the faceZone for the baffle creating I mentioned in the last post.

Andrew

[A.Wendy]

hi

have you created to seperate meshes?

maybee this thread could be usefull for you
pimpleDyMfoam simulation keeps blowing up

best wishes

Andy

[ADGlassby]

Andy,

Thank you for your suggestion. I will rework my meshes as you suggest in your other post.

In short I have been trying to do all the meshing in one file which I suspect was the wrong way to do it.

I will repost here when I have results.

Best Regards

Andrew

[ADGlassby]

Hi Andy,

I'm running 2.2.x on Mac OS X and I get the following when I try to run pimplDymFOAM

--> FOAM FATAL ERROR:
Attempt to cast type wall to type lduInterface

From function refCast<To>(From&)
in file /Users/andrewglassby/OpenFOAM/OpenFOAM-2.2.0/src/OpenFOAM/lnInclude/typeInfo.H at line 114.

FOAM aborting

Don't know it you've seen this ?

I have managed to create the mesh so I'm going to follow it through more closely now to understand your logic.

Best Regards

Andrew