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-   -   Star CCM Overset Mesh Error (Rotating Turbine) (http://www.cfd-online.com/Forums/cd-adapco/114253-star-ccm-overset-mesh-error-rotating-turbine.html)

thezack March 7, 2013 12:42

Star CCM Overset Mesh Error (Rotating Turbine)
 
Hi, I am having an error in my simulations that I cannot seem to fix. I have a turbine (DFBI 1 axis rotation) rotating inside of another larger mesh. The purpose of the simulation is to simulate a gravitational vortex turbine (water enters from the top of a funnel and swirls down the funnel creating a vortex, and a turbine is placed at the bottom to rotate a shaft). The simulation is 3D. Mesh 1 is the polyhedral mesh of the funnel volume, and mesh 2 is the overset mesh of the turbine completely enclosed within mesh 1. Both are polyhedral mesh, mesh 2 has prism layer mesher, surface remesher, and surface wrapping meshing models. Mesh 1 has polyhedral, prism layer, and surface remesher.

I keep trying varying levels of mesh size for mesh 1 and mesh 2, and I keep getting this error message:


Updating indirect region interface Overset Mesh 1 between Turbine and SwirlyMarch5NoDamEntrance.
Failed to cut hole in region SwirlyMarch5NoDamEntrance.
This might be due to an overlapping of overset regions or due to invalid mesh configuration!


Am I using the wrong meshing models? Should mesh 1 or mesh 2 be finer? Should they be roughly the same mesh size or should 2 be much finer? I am new to this, and I have no idea how to proceed. I keep messing around with the mesh properties and nothing seems to work. I am not sure if there is something specific I should be changing. The documentation on Star CCM+ has a troubleshooting section, but it does not say how to fix those kinds of errors. Ive tried setting up the scalar overset mesh type scene, but of course it is in 2-D when my simulation is 3-D, so I cannot see where on the mesh the error is. I am pretty stumped here and would greatly appreciate any help. Thanks!

ryancoe May 14, 2013 15:08

Zack,

The overset mesh can be challenging to configure. I've had some luck using a series of plane sections with the Overset Scalars to try to find the locations where you're having problems. Its a bit unwieldy, but its the best thing I've found thus far.

If that doesn't help, I would try to simplify the geometry to make it more overset-friendly until you get it working, and then work back to full fidelity.

hyderkhan74 September 27, 2013 07:58

Hi
I have the same problem so i wonder how you solve it ?
thanks in advance

ayannath23 December 11, 2013 03:09

Hi Zack,
I think the error is due to improper mesh..
Please go through the tutorial in star ccm+ help (Tutorial Guide > Motion > DFBI: Lifeboat with Overset Mesh). It explains nicely about the meshing requirements.

Thanks,
Ayan


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