[LESlie]

Hi Foamers,

I am working on needle transient motion of injectors and I have implemented my own class with layer removal based on movingTopoFvMesh. The injector mesh is converted from a fluent mesh. What I did is to find the patch, say NEEDLE with

label patchID = boundaryMesh().findPatchID("NEEDLE");

Info << "patchID = " << patchID << endl;

const polyPatch& cPatch = boundaryMesh()[patchID];

then put the faces of this polyPatch as extrusion faces for the mesh modifier, and also mark the points on these faces for the motion, so that only these points will be moved.

The code is working in serial mode (attached pictures), however failed in parallel.

Serial log file
Create mesh for time = 0.0002

Selecting dynamicFvMesh needleTopoFvMesh
Initial time:0.0002 Initial curMotionVel_0 0 1)
Time = 0.0002

Adding zones and modifiers to the mesh

patchID = 1
cPatch =
type wall;
nFaces 20732;
startFace 3529376;

number of face in zone1 20732

Adding mesh zones.
Adding 1 mesh modifiers
patchID = 1
number of points marked 20986

.... reading data....

time:0.0002000017749 curMotionVel_0 0 1)
No topology change
Executing mesh motion
Execution time for mesh.update() = 1.67 s

..... flow calculation .....

Total Volume change = -3.598473946e-15
ExecutionTime = 31.52 s


Parallel log file
Selecting dynamicFvMesh needleTopoFvMesh
[0] Initial time:0.0002 Initial curMotionVel_0 0 1)
Time = 0.0002
Adding zones and modifiers to the mesh
[1] Initial time:0.0002 Initial curMotionVel_0 0 1)
[2] Initial time:0.0002 Initial curMotionVel_0 0 1)
[3] Initial time:0.0002 Initial curMotionVel_0 0 1)

patchID = 1
cPatch =
type wall;
nFaces 0;
startFace 879157;

number of face in zone1 0

Adding mesh zones.
Adding 1 mesh modifiers
patchID = 1
number of points marked 0

.... reading data....

time:0.0002000017749 curMotionVel_0 0 1)
No topology change
Executing mesh motion
Execution time for mesh.update() = 1.67 s

..... flow calculation .....

Total Volume change = 0
ExecutionTime = 14.72 s


Apparently when running in parallel (4 procs), polyPatch& cPatch = boundaryMesh()[patchID] failed to create the polyPatch. I am running on 2.2.x. I would really appreciate some help on this!

Have a nice day!

[LESlie]

Originally Posted by LESlie

Hi Foamers,

The code is working in serial mode (attached pictures), however failed in parallel.

I am running on 2.2.x.

However I did a test with a simple mesh created by blockMesh (attached pictures). In that case the code IS WORKING in PARALLEL!

I am using scotch decomposition method. I checked that in this simple test case, the moving patch is distributed evenly on 4 processors.

In case/constant/polyMesh/boundary

NEEDLE
{
type wall;
nFaces 80;
startFace 4770;


And the parallel log file:
Create mesh for time = 0

Selecting dynamicFvMesh needleTopoFvMesh
[1] Initial time:0 Initial curMotionVel_0 0.1 0)
[2] Initial time:0 Initial curMotionVel_0 0.1 0)
[3] Initial time:0 Initial curMotionVel_0 0.1 0)
[0] Initial time:0 Initial curMotionVel_0 0.1 0)
Time = 0
Adding zones and modifiers to the mesh
patchID = 1

cPatch =
type wall;
nFaces 20;
startFace 1170;

number of face in zone1 20

Adding mesh zones.
Adding 1 mesh modifiers
patchID = 1
number of points marked 42


What is the mysterious reason behind all of this?

[LESlie]

Originally Posted by LESlie

However I did a test with a simple mesh created by blockMesh (attached pictures). In that case the code IS WORKING in PARALLEL!

I am using scotch decomposition method. I checked that in this simple test case, the moving patch is distributed evenly on 4 processors.

It's me again.

The 2nd simple case works in parallel only when it is 2D. When I run it in 3D, parallelization failed also.

[hjasak]

You need foam-extend-3.0 Parallel topo changes are one of the new things I have done for this release. Please beware: if you have written your own dynamic fvMesh class, you may need to update it to handle parallelisation as well.

Hrv

[LESlie]

Originally Posted by hjasak

You need foam-extend-3.0 Parallel topo changes are one of the new things I have done for this release. Please beware: if you have written your own dynamic fvMesh class, you may need to update it to handle parallelisation as well.

Hrv

Thanks for the reply.

However the movingConeTopo tutorial crashes, log file indicates:

Volume: new = 1.768551e-09 old = 1.768573998e-09 change = 2.299798524e-14
Courant Number mean: 196.2985037 max: 1992315.801 velocity magnitude: 1077.436077
deltaT = 1.277645154e-09
Time = 0.4066660041



--> FOAM FATAL ERROR:
negative cell volume. Error in mesh motion before topological change.

From function bool layerAdditionRemoval::changeTopology() const
in file polyMeshModifiers/layerAdditionRemoval/layerAdditionRemoval.C at line 295.

FOAM aborting

Aborted (core dumped)

[hjasak]

Fixed and about to push:

BUGFIX/cellLayering

Apologies,

Hrv

[bsiyahhan]

Hello All

I am recently experimenting with mesh motion in foam-extend-4.1. Using a 2D mesh I was able to implement some mesh motion successfully but when I tried to move to 3D I get an error due to negative cell volumes.

--> FOAM FATAL ERROR:
negative cell volume. Error in mesh motion before topological change.

From function bool layerAdditionRemoval::changeTopology() const
in file polyMeshModifiers/layerAdditionRemoval/layerAdditionRemoval.C at line 306.

FOAM aborting

Aborted (core dumped)

The case is quite simple a cube within a channel and what I observe is that the error occurs first time when a layer is to be added. Instead of adding the layer inside the enlarged one it is added next to it, as it has negative volumes. Am I missing something real simple here, perhaps using a wrong convention in mesh or zone definitions?

[2538sukham]

I am quite new to OpenFoam but i think the negative volume arises when the layer movement is faster than the removal resulting in negative cell volume. try lowering the timer step or maybe the layering is not working.