[hamedc]

In a typical CHT simulation in CONVERGE software, I encountered two issues related to importing parts with imposed interfaces:
1) If you import as STL via "import CAD file", a relatively high number of overlapping tris errors appear in the diagnostics tab. How to overcome this error?
2) Fewer errors appear if you import as STEP/IGES via "Import CAD File" (mesh is selected as triangle and quality as fine). However, the mesh quality (i.e., triangulated) is very poor. How to refine the mesh after importing by this method?


Thanks,

[lmy_csi]

Hi Hamed,



1) I would suggest deleting interface in your CAD STL file, and then manually using the "Repair -> Patch" to create the interface in CONVERGE Studio; Or use the "Repair -> Surface -> Delete overlapping boundaries" to delete overlapped surfaces. I assume you are using v3.1.

2) You can use "Mesh -> Surface -> Triangulation -> Regine triangles" to refine the mesh.



Please let me know if this works.



--------------------------------------------------------------------------------
Mingyi Liang

Research Engineer, Applications
Convergent Science

[MFGT]

direct CAD File import with Triangle Mesh and Fine Quality should give a very good triangulation of the surface, in my experience.
You can add Smooth Gradation under the import settings as well.

[RR06]

Originally Posted by MFGT

direct CAD File import with Triangle Mesh and Fine Quality should give a very good triangulation of the surface, in my experience.
You can add Smooth Gradation under the import settings as well.

@MFGT have you noticed significant changes to solution and runtime with this?

I did when attempting to move from stl to CAD import. I am keen to move to CAD import to allow some scripting to auto-assign boundaries from CAD model

[MFGT]

Well, I guess there is an influence, but I mainly noticed the following:


fine triangulation -> large surface.dat file -> larger post.h5 files

[hamedc]

Thank you both, Mingyi and Tobias,


I have another problem in simulating the oil gallery of a composite piston, which has nut, pin, and sleeve (solid-to-solid contact) and so on. I simplified the model as possible. But two remaining issues does not solve yet:


1- Unlike the HSDI diesel example, the oil jet placed on the liner stretch, then I cannot loft directionally the bottom of skirt to a crankcase. Therefore, I got this warning: “There may be an alignment issue between ….” Is there any hint/trick to fix this?


2- The model has 5 streams (0 for oil gallery and crankcase, and 1-5 for solid parts which have the same moving profile such as skirt, piston, sleeve, nut, and pin). In the diagnosis tab with “Check stream consistency for interface boundaries” marked on, there are no errors to display. But, these errors appear when running the case:
“(Rank 3) stream 4 triangle vertex[2] location: (x,y,z) ( -7.2444437e-03 1.9416318e-03 -3.2007703e-02)
(Rank 3) FATAL_ERROR: [2129] neighboring triangles on boundary 48 and 58 are associated with different streams--this is not allowed.
I checked all normal orientations of interfaces to properly point the forward and reverse.


Thanks,

[lmy_csi]

Hi Hamed,



The information you shared is very limited for me to help you solve the problem. We may have to take a close look at the case setup, surface file, etc.. You can reach out to CONVERGE's support team for furthur help, by emailing support@convergecfd.com.