[rrschor]

Hi,

I get this error message every time I try to run my case.

The parallel block size (dx, dy, dz) is 2.560000e-001 2.560000e-001 2.560000e-001.
JOB ABORT invoked by rank 0:
ERROR: could not find a side polygon that surrounds the negative area side polygon
this means the stl file probably has problem areas
(-6.791250e-004 5.849926e-002 -4.603075e-001)

How can I fix this? Or the only whay is to try to repair the .stl geometry?

PS: I followed the tutorial for PFI injection and during the geometry check "Diagnosis Dock" I did not find any error.

Best regards,

Roberto

[alemoine]

Hi Roberto,

This message is directly related to an error in your geometry. The error message CONVERGE writes provides you with coordinates which correspond to the problem area in your geometry --> (-6.791250e-004 5.849926e-002 -4.603075e-001).

In CONVERGE Studio, you can create a Vertex with the coordinates provided by the error message. Once the Vertex is made (it will be represented by a red dot on your geometry), you can get a better look at the problem area. Do you notice anything that could be potentially problematic at this location? Is there a sharp edge or any complex curvature in this area?

When you run the Diagnosis in CONVERGE Studio we check for intersecting triangles, open edges, non-manifold edges, normal orientation, and isolate triangles by default. However, sometimes there can be other issues that may or may not present a problem when running your simulation.If all of these default checks are coming up error-free, then you should include the "overlapping triangles" and "small angle" options in your diagnosis. Rerun the Diagnosis and look at the problem area to see if the surrounding triangles contain any of these additional defects.

If this does not help, would you be able to take a snapshot of the problem area in your geometry and post it here?

Thank you,

[rrschor]

Hi alemoine,

I plotted the vertex into and it is outside of the cylinder (outside of everything actually).

1.PNG

2.PNG

The Diagnose tab still don't recognize any errors.

Best regards,

Roberto

[alemoine]

Hi Roberto,

Could you check that all of the normal vectors are pointing into the computational domain? Do this manually by clicking the "Normal Toggle" button located on the left-hand side of CONVERGE Studio.

Since you most likely have triangles in motion, it would also be helpful to use the Animation function to check for triangle intersections during the motion. You can do this by going to View Options > Animation and select the "Check triangle intersection in each step". By clicking the "Reset" button, Studio will check your input files to set the start and end times of your simulation.

Thank you,

[RaphaelM]

Hi Allie,

Just like Roberto, I had the same error that he had:

JOB ABORT invoked by rank 1:
ERROR: could not find a side polygon that surrounds the negative area side polygon
this means the stl file probably has problem areas
(-3.267911e-002 -2.886728e-004 8.210181e-003)

If I create a vertex using this coordinates, the vertex is outside the surface:





I have checked the normal vectors orientations and ran the animation to check triangle intersection, but converge do not find any errors.
Do you have any idea how I can fix this?

Thank you,

Raphael

[MFGT]

Hi Raphael, we cant see the images. You have to upload them to some filehoster.

[RaphaelM]

Hi Tobias! My bad... I've corrected the images, thank you.

[alemoine]

Hi Raphael,

If the aforementioned suggestions did not help detect the error, then it would be best to email your geometry and question to support@convergecfd.com.

Thank you,

[RaphaelM]

Hi Allie,

I finally found what was wrong in my case setup.

The exhaust valve direction was pointing toward the z+ direction and I simply inverted the vector sign. As my simulation start time was during the exhaust stroke, I believe that the exhaust valve was opened but in the opposite direction, what leaded to STL conflicts right in the indicated point.

After changing just the valve direction vector sign the simulation has started to work.

Raphael

[topperz]

Thanks Raphael.
Your input was helpul

[dinesh1700]

m also getting the same error during IC Engine simulation. diagnosis is showing no error.
please help

[MFGT]

Hi dinesh,


create a vertex at the mentioned location and search for suspicious triangles or geometry deformation.

[EDE16]

I had the same error before, vertex was well below my piston at BDC. Problem turned out to be units!, my valvelift data had been input in mm rather than meters.