Furthermore the i. b. layer create three illegal faces.
Checking faces in error :
non-orthogonality > 70 degrees : 0
faces with face pyramid volume < 1e-13 : 0
faces with concavity > 80 degrees : 1
faces with skewness > 4 (internal) or 20 (boundary) : 0
faces with interpolation weights (0..1) < 0.02 : 0
faces with volume ratio of neighbour cells < 0.01 : 0
faces with face twist < 0.01 : 2
faces on cells with determinant < 0.001 : 0
Finished meshing with 3 illegal faces (concave, zero area or negative cell pyramid volume)
But im sure the are “adjusting skrews” to avoid the illegal faces and do a nice mesh without any illegal faces .
Which option i have to change to get a nice mesh ?
Well an easy thing to do if you’re in a hurry would be to just switch from the Hex dominant parametric to Hex dominant. For “Fine” or “Very Fine” fineness, there is notable change in the Arch, as you can see here . If you want to use the parametric though, I can revisit this.
Best regards,
Fillia
@Kai_himself: Mind that you can run simulation with some illegal faces. It is often a trade-off, as mesh size without any illegal face can be huge. So for first quick and dirt simulation I suggest to use small, but not so perfect meshes.
Sorry @Retsam, but in this particular case I have to disagree with you.
Not because I think that having these 3 illegal faces here will make much difference in the results, but because Kai has put so much effort into this project (as we both have been seeing), and we can be pretty sure that Kai is not looking for ‘eye candy’ results.
If he wanted ‘eye candy’ results, he would have had them within an hour or so of finishing his geometry
My experience with obtaining ‘accurate’ results is that you MUST follow ‘best practices’, if for no reason other than being able to ‘rule out’ issues like these illegal faces as a reason that you are not getting expected results (which in this case, includes the question, why are my layers collapsing in some places)…
AND, even with ‘best practices’ adhered to, I would consider myself ‘lucky’ if the results were within 15-20% of any experimental data (if the experimental data would even be available, if it is not available then all the more reason to follow best practices)…
To erase the three illegal faces, i increase the surface refinment to level 2 (from level 1), and now there are no illegal faces, in my model. Now i will check rohits geometry, and Dales values mentioned in his y+ topic.
Sooo, i tried a few new options to creat a good inflatable layer, but i was not succesfull .
I ran a few simulations on the Mesh 5 569k. This is the first inflate layer mesh attempt.
At all simulations the time step decrease fast to very small timesteps, like 3e-11 till -105.
I think it depends on the Mesh, even though the mesh was created without any error.
The following three pictures shows the Mesh 5 569k.
I think when you relax some meshing parameters to retain more BL cells, that the reporting of illegal faces sets new ‘looser’ standards for what is an illegal cell… (I could be wrong there but that is my memory)…
So, those same, previously reported illegal cells may still be there… and may no longer be reported as illegal
Have you looked at the numerous ParaView quality stats on the meshes
Yes, that filter calculates many different quality metrics for any mesh…
Don’t ask me about the relevance of them though… I have only used them a little for relative comparing between two meshes so far, there must be some docs on what the magnitudes of the different values though…
Hey,
i have been trying out a little.
At some spots the layers still collaps, specially at the surfaces and some corners.
I think that’s negligible for now and the simulations runs through.
In the first run i got a “strange” behaviour. It looks like the water crawls up the hill, without raising waterlevel.
The inlet velocity is 0,0212 m/s (0,05 m³/s).
I make two runs, with and without the inflate boundary layer.
The waterlevel was measured at the same spot.
.
, so it has to be accurate.
.
…
