Solve error and Model gap error

[Defo74]

Goodevening,

I've got a question about a 'mesh/solve' problem.

Here is the thing:

When I load my drawing in CFD no problem.

I do get the message that it might be better for the model to merge it.

After I've doe that everything goes well until I get to the solve part.

First I use the Automatic size button like always.

Then my Surface and my Gap refinement say: false and my length scale :0.008 (No red/strange messages in the output bar yet)

I press the Solve button and the computer does his thing.

After a while I get the following message:

General Meshing error (60/503)

I don't know what is means, but I then use the surface and the gap refine button in the mesh edit.

After a few minutes get the following message is shown in the output bar:

Model gaps in the range of 0.000115628 to 0.008 have not been resolved to specified constraints.

After this don't know what to do.

Can somebody please help me.

Thanks,

Dwane 

[Jon.Wilde]

Hi Dwane,

Thanks for posting this.

It is probably best if you can share your CFZ file with us.

Can I ask why you are using the surface ad gap refinement? Was there something that promted you to enable them?

Kind regards,

Jon

[Defo74]

Good evening Jon,

I'm sorry, I can't share the file because it is a prototype racecar.

I used the refinement because I had the gap error and I thought that refining the gap maybe solve the error.(That says: that the gaps in the range of 0.000115628 to 0.008 have not been resolved to specified constraints) It didn't help.... Maybe you know something to try?, because I'm out of ideas.

Kind regards,

Dwane

[Jon.Wilde]

Hi Dwane,

I appreciate the secrecy but it is going to be tough to help you here. Do you have many small gaps or features in the model?

Have you tried without the surface refinement? What made you use it in the first place?

Maybe a manual mesh might work?

Kind regards,

Jon

[Defo74]

Hi Jon,

When I have the model in Inventor and I will try to look for gaps or errors, nothing will be found.

I find it strange that in Inventor no errors or something is found, but in CFD the model doesn't function as it should do.

I've also tried to do it without the refinement but it didn't make any difference.

The reason why I used it was; because I just tried to find a way on how I could make the model work.(a real deep thought and good idea wasn't the case here)

Maybe it is useful to know that the model was a 3D scan of the real car and that there are a lot of small details on the model.

I don't know that if a object is build out of a lot of small ''surface detail'' that errors will occur sooner.

I haven't tried a manual mesh yet , maybe that is the solution.

But I haven't used I before so I don't know what values to use....

Kind regards,

Dwane

[engr_jake1925]

Hi Jon & Dwayne,

I have the same problem. I checked my model many times but i have the same error whenever i run the solver.

If you have any solutions for this kindly forward to me as well.

Btw, i attached my CFD file maybe if you want to review it.

Thanks a lot.

Regards,

John

[Jon.Wilde]

Please check you are running from your C drive, the files must all be held locally.

I cannot see a file to check but would be happy to do so if you can send it over.

Kind regards,

Jon

[pareanna]

I got the same problem, I tried to change the geometry and simplify it but nothing works.

You can see attached my file.

Thanks

[LKania]

The message regarding gap refinement limits displayed when the Surface Refinement option is used indicates that part proximity is such that mesh size specifications are insufficient to adequately resolve the detected gaps. Without knowledge of the particulars of your model, whether these gaps are "real" or the result poor model construction (i.e. model deficiencies) cannot be ascertained. It's a god bet that when this message is displayed that the meshing operation itself will be touch and go.

Manual meshing may enable one to gloss over these regions of the model, but then it's up to the user to define appropriate mesh sizes.

[jon.norris08]

Thin walled parts created in inventor, with edges shorter than 3mm this mesh engine seems to struggle with, CFD Suggests using gap refinement, You then get a message Model gaps in the range of 0.00033223 to 6 have not been resolved to specified constraints. Slightly confusing with refinement tolerance being as large as it.  

Solution I have found, either set the gap refinement length to minimum setting before refining or you have to use diagnose tool and add all of these issue edges to a group, highlight the group in study bar, then use edit tool. Slide mesh size adjustment to a fine setting, click apply then generate mesh. reducing size until your mesh generates without gap errors. 

using interference tool in inventor helps check model for issues, however doesn't seem to solve the issues cfd has with short edges but worth using this tool initially. 

[jon.norris08]

Thin walled parts created in inventor, with edges shorter than 3mm this mesh engine seems to struggle with, CFD Suggests using gap refinement, You then get a message Model gaps in the range of 0.00033223 to 6 have not been resolved to specified constraints. Slightly confusing with refinement tolerance being as large as it.  

Solution I have found, either set the gap refinement length to minimum setting before refining or you have to use diagnose tool and add all of these issue edges to a group, highlight the group in study bar, then use edit tool. Slide mesh size adjustment to a fine setting, click apply then generate mesh. reducing size until your mesh generates without gap errors. 

using interference tool in inventor helps check model for issues, however doesn't seem to solve the issues cfd has with short edges but worth using this tool initially.