Hello - further meshing tests.
I’ve spotted something on ROV’s hull elements and decided to check it with a use of a simple geometry. Deliberately I took sphere (ball) and torus elements. And to make two things at ones one ball and one torus were cut into half, the other weren’t. The reasons for this were as follows:
Missing torus elements | I remember that in the past it was quite a common problem while importing and exporting geometry. Changing format from one to another often led to missing parts. What they had in common however was lack of clearly defined generatrix for this particular elements – torus is an excellent example. So, below is what I saw at the first time.
Solution to this is very simple: just cut element anyhow to make additional edges which help to identify the shape.
Strange mesh refinement at bow and BL issues | I’ve mentioned about it in my previous post. Later on I changed input geometry and I noticed that unexpected refinement occurred only in situations when I’d cut bow section into half. In case where I had left it as a semi-sphere the mesh was okay.
Now quick, simple test and its results:
Basic geometry
Elements in the foreground are the ones cut in half (highlighted). What’s interesting, importing torus as an independent element program automatically split it into two parts – well done.
Sphere however maintained its generatrix from CAD program (which I guess allowed shape identification) – super.
Unfortunately, Boundary Layer generation went worse :-/
Below we have overall view of surface mesh at particular elements. Please notice one very important thing I have also experienced during ROV mesh generation (!).
I have no idea what it is. It seems that mesher splits surface according to some strange scheme and then assigns mesh in this peculiar way. I would say it has an influence on results. Except problems with BL I have noticed significantly worse residuals too. - Anyone has any idea or explanation to this?
Volume mesh – cut at XY plane (so that all elements could be seen).
This time I didn’t bother myself to colour BL. As you can see proper BL (I have no objections to it) was generated at cut sphere only. The other sphere and both torus have no BL.
Volume mesh – cut at plane YZ (picture showing two previously cut elements).
Volume mesh – cut at plane parallel to YZ (picture showing two previously uncut elements).
