CFD Online Discussion Forums

CFD Online Discussion Forums (
-   STAR-CCM+ (
-   -   Problem with Baffles (

eRzBeNgEl September 13, 2011 15:05

Problem with Baffles
Hi guys

I am analysing two fans in a series connection. Between the two fans there is a straightener in the shape of small tiny cylinders. Therefore I created the straightener in Catia as area (no Volume).

My following step is to import the straightener area as STEP File into CCM+. Then I combine ("Combine") then with a volume (the straightener is inside of this cylindric volume). My next step ist "Convert to interfaces" and set the Interface type as Baffle.

Now, when i start to create the polyhedral mesh there is always a error message while it is creating the tetra meshing step. (Error: x51265465, Error SYJavaetc...etc....)

Where is the problem? Can anyone help me?

My Mesh Setup is Polyhedra Meshing, Surface Remeshing, etc..

kyle September 13, 2011 15:26

It sounds like you doing things the wrong order which is giving you an interface between two boundaries that lie within the same region. The straightener will likely need to be a completely separate region from the fans. Here is the process you need to follow:

After you import your straightener geometry, do not combine it with any of your existing regions. You need to do a "Convert to Interface" on the boundary that you want to become the upstream interface. This will create one new boundary and one new interface. You must now move the new boundary to the upstream fan's region by first creating a new region from that boundary, and then merging that boundary with the the upstream region. Then, you need to repeat the process with the downstream interface.

If you are not using the surface wrapper or you desire a conformal mesh, then you will be required to take some additional steps.

This process is convoluted, unintuitive, restrictive and should be much simpler. It represents everything I loathe about Star-CCM+.

eRzBeNgEl September 13, 2011 16:25

Thanks Kyle, Iīll try it tomorrow and will give u feedback.......

eRzBeNgEl September 14, 2011 03:44

2 Attachment(s)
Hi Kyle,

Ok, i donīt get your instruction in the right way I think. In the attachement you can find two pics of my problem.

I have got two regions. One Region is the Fluid Cylinder and the other region is the Honeycomb Straightener as areas.

1st Step: Click on Honeycomb Boundary and "Convert to interfaces". Now i got two boundarys building a interface (click on type as buffle).

2nd Step: Click on one Interface Buffle Boundary and "Create new Region from Boundary". There are two Regions including one Boundary of the Baffle Interface now.

3rd Step: Combining of one Baffle Type Boundary with the Fluid Cylinder Boundary...

Is this right? Or do I get something wrong?

eRzBeNgEl September 14, 2011 07:11

Ok, it is still not working:

It can build the surface mesh but not the volume mesh. Always this failure appears:

"canīt recover edge near position (xxxx,yyyyy,zzzz)"

Can anyone help me? I do not know what to do and also the support is not helping. I can send u the *.sim File. It is small and about 7,8 MByte.

All times are GMT -4. The time now is 20:26.