Hyperworks CFD Volume mesh failed, node collapse

James Moody

Hello,

I'm getting a volume mesh failure in Hyperworks CFD, caused by "Warning: 1 nodes found to have bad topo."

I assume this is the node ID: "n1203618(ni177756)"

Is it possible to find and fix the node which is causing this "10 elems resulted in invalid cfgs due to node collapsing. (has error highlighted)10 elems failed and saved."?

And if not is there another method to fix the issue?

Log file attached

Thanks!

acupro

James Moody said:

Thank you, that's incredibly helpful! For future reference, please could you explain to me the process of creating that area?

This was a process of splitting surfaces using 'Interactive' - where we click and hold to select the first trim end and drag to select the second trim end, then release.  Here I use the default snap functions to make the split line perpendicular.  I do this to a few surfaces.  (I also did this to two of the airfoil surfaces as mentioned earlier.)  Then use Create Surfaces using Patch to create the new surfaces.

Deleting the surfaces deletes the solid topology - so the solid needs to be re-created before validating again.

acupro

Very difficult to diagnose what is happening here.  Are you able to attach the HyperWorks CFD database here?  If not - probably best to open a ticket directly through Altair Support.

James Moody

Hi, yes sorry I didn't really know how to describe the problem. Unfortunately the HM file is too large to attach, thanks though!

acupro

James Moody said:

Hi, yes sorry I didn't really know how to describe the problem. Unfortunately the HM file is too large to attach, thanks though!

If you make sure any volume and surface mesh are deleted (delete surface mesh also deletes volume mesh) then save the HWCFD database - does compressing that make it smaller?

James Moody

I've attached the HM file with the mesh deleted. I think the issue is the base geometry is quite messy (even though I've tried to clean it up) as it's lifted straight from a wind tunnel model CAD file. Thanks!

acupro

James Moody said:

I've attached the HM file with the mesh deleted. I think the issue is the base geometry is quite messy (even though I've tried to clean it up) as it's lifted straight from a wind tunnel model CAD file. Thanks!

I split the surfaces on a couple of the airfoil sections - near the leading edge.  I also recreated one area to get away from the volume inside a tiny angle - as shown in the image within the cursors.

 

Make sure the mesh sizes (surface and BL) still are for the correct groups, as some surfaces may be in incorrect groupings now.

James Moody

acupro_21778 said:

I split the surfaces on a couple of the airfoil sections - near the leading edge.  I also recreated one area to get away from the volume inside a tiny angle - as shown in the image within the cursors.

 

Make sure the mesh sizes (surface and BL) still are for the correct groups, as some surfaces may be in incorrect groupings now.

Thank you, that's incredibly helpful! For future reference, please could you explain to me the process of creating that area?

acupro

James Moody said:

Thank you, that's incredibly helpful! For future reference, please could you explain to me the process of creating that area?

This was a process of splitting surfaces using 'Interactive' - where we click and hold to select the first trim end and drag to select the second trim end, then release.  Here I use the default snap functions to make the split line perpendicular.  I do this to a few surfaces.  (I also did this to two of the airfoil surfaces as mentioned earlier.)  Then use Create Surfaces using Patch to create the new surfaces.

Deleting the surfaces deletes the solid topology - so the solid needs to be re-created before validating again.