Continuity problem with a multiphase simulation


#21

Hey @Get_Barried,
i tryed too mesh it, but it wont work. I had this failure on a other model of mine.
Simscale said the geometry is watertight, and i set a material point inside the model.
Here is the link.
What do i wrong ?
Greetz Kai


#22

Hi @Kai_himself,

Wow thats really weird. Let me copy the project over and see what I can do. Do keep trying in the meantime.

Cheers.

Regards,
Barry


#23

Hi @Kai_himself,

Your simplified geometry is not simple enough, there are several faces which are completely un-needed and are only for the finished construction rather than a test case. If you refer to the pictures below you can see where I feel that the features can be simplified.

The box covering the entire center is not needed and can be removed.

Same here as the red highlight is where I would define one of my outlets.

The Inlets and other pipe outlet does not require such a complicated cap, a simple flat closed face with zero thickness to keep the model watertight is sufficient for both ends. Your current geometry has intersections especially at these parts.

Same issue here, you points at the box where the pipe connects has additional features that can be removed. A circular pipe attached the box is fine.

If you keep this simple with no intersections we can start on the simulations.

Cheers.

Regards,
Barry


#24

Hey @Get_Barried,
Thank you for your effort. Ok i will try it when i at home, today afternoon.

Can you show me how you creat that mesh ? If i try it, it dosent work.

Greetz Kai


#25

Hi @Kai_himself,

It is just a simple auto “Hex-dominant automatic (only CFD)” mesh to just see the quality of it around the current geometry. You can do the same with relative ease. This refinement level is only 3.

Cheers.

Regards,
Barry


#26

@Get_Barried,
ok, thank you. At my try i use Hex-dominat parametric.


#27

@Get_Barried,
so i made a few changes. I try to make the pipes and the cover flat (surface). It looks watertight, and i use the same fixed link between the surfaces. Unfortunaley the model is not watertight. Here is the onshape link and here the simscale link.

Greetz Kai


#28

Hi @Kai_himself,

I’ve modified your geometry so this is what it should be.

However, I’m unable to export it to simscale for whatever reason, maybe you’ll have better luck than me. Do try it out.

Cheers.

Regards,
Barry


#29

@Get_Barried Again thank you for your effort.
I dont know the funktion delet area in onshape.

i cant import the model in simscale, “Your file could not be processed successfully. Please check the file format and try again.”. Maybe it has something to do with the surfaces ?

Greetz Kai


#30

Hi @Kai_himself,

Not sure what is wrong. Maybe try in a different CAD software? I’m not too familiar with OnShape yet.

Cheers.

Regards,
Barry


#33

Good morning @Get_Barried ,
i think i got it :).

i imported it as stl, with the pipes, after the import i have to scale and split the surface into single surfaceses.

Greetz Kai


#34

Hi @Kai_himself,

Great! Do let me know how it goes. STL is quite a problematic format so lets see how it performs.

Cheers.

Regards,
Barry


#35

it work not well. I got this message when i try to mesh ist “The tesselated surface is not closed. There could be a problem with the CAD geometry (such as self-intersections). Please inspect your geometry. Trying to proceed anyway.” i dont see any hole or something.
The simulation broke up at 0.0011 seconds.

How do you creat your 3d models ?

Greetz Kai


#36

Hi @Kai_himself,

I do my 3D models offline in AutoCAD or Solidworks. Maybe you can try there?

Cheers.

Regards,
Barry


#37

Hey @Get_Barried,
i will try it, in AutoCAD.
I wrote the support to, i get a free STEP online viewer, here is the link, the geometry is shown correctly…
Strange that i cant upload it here.

Greetz Kai


#38

Hi @Kai_himself,

Very strange indeed. Do try out AutoCAD and let me know how it goes.

Cheers.
Regards,
Barry


#39

Hey @Get_Barried,
i got it. SimScale cant handle geometrys only out of surfaces.
If you use Hex-dominat parametric it only meshes the inner wall, i also change the boundry conditions pressure out, to custom pressure inlet-outlet velocity.
I think it runs :slight_smile:
Greetz Kai


#40

Hi @Kai_himself!

Good stuff! Do post some much awaited post-processing screenshots and data here :stuck_out_tongue:

Cheers.

Regards,
Barry


#41

Hey @Get_Barried,
Thank you for your help.
I make videos with the Shaft simulation, it was the same problem.
Here are the links. :slight_smile:
Video 1
Video 2
Video 3

Winamp speed 2 is recommanded :slight_smile:
I will definitely get back to you with further problems :slight_smile:

Have a nice weekend
Kai