cfdOF install

[thschrader]

I also had to fiddle with things when I began working on the second inlet.
More fiddling than with the first inlet.

In the tutorial the elbow-sketch is written on the xy-plane. You wrote
the sketch on xz-plane, you must use z-direction for inlet 2.
When using gmsh, the solver converges, when using cfmesh (2D-option)
the solver does not converge
everything depends on the mesh...

test_elbow_1_new_gmsh.FCStd

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test_elbow_1_new_cfmesh.FCStd

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[ljb]

Thank you Syres
It was a visibility issue

******

Thank you thschrader

You wrote the sketch on xz-plane, [so] you must use z-direction for inlet 2.

I did not get to the point of entering velocity value for inlet2 last night, but I see now that setting it for Y instead of X would have had me running in circles. When I first read this, I though I was going to have to re-do my sketch. But then I woke up and figured out the easy way.

I went back over the tutorial, looking for where it specifies the plane, and could not find it ...
(If it is really obvious, just chuckle at me and I'll dig some more. I suppose it is implied by the velocity for inlet2, but I would hope for something explicit.)

When using gmsh, the solver converges, when using cfmesh (2D-option)
the solver does not converge

I thought I used gmsh, as the tutorial says. How do I go back to see what I did?

This also get me back to some of the 'fiddling' I have to do. Sometimes the display won't behave like the tutorial says it should.
For example, right now I can't get the cfd tool icons to work - most of them are grayed out. Only 'Create analysis' and 'Create a mesh' are available.

Also, the task tab in my combo view is empty for everything in the tree.

Never mind - I was 'fiddling' with the project tree and the task tab activated. I think I double-clicked on inlet1
But my cfd tool icons are still gray. In fact, now all of them are gray.

[thschrader]

The xy-plane is specified on page 5 tutorial. „Start a new sketch“, point 5.
You can draw the sketch on any other plane, but adjust the inlet direction.
When you activate the cfd-workbench after designing your fluid-domain, all icons except analysis are greyed.
Click on analysis-icon, more icons are active. Click on your body in model-tree, the mesher
icon is active. Thats a normal behavior.
When you load an existing case, most icons are greyed out. Doubleclick on
Cfd-Analysis in model-tree for activating them.
Try this with the files I posted above. Have fun with cfd

activate cfdOF-workbench.JPG (37.12 KiB) Viewed 1867 times

create_analysis.JPG (40.77 KiB) Viewed 1867 times

mesher-active.JPG (43.17 KiB) Viewed 1867 times

load_existing_case.JPG (48.73 KiB) Viewed 1867 times

doubleClick_cfdAnalysis.JPG (50.06 KiB) Viewed 1867 times

[ljb]

Thanks

The xy-plane is specified on page 5 tutorial. „Start a new sketch“, point 5.

Ah yes. Now that I know where it is, I can't not see it.

Try this with the files I posted above. Have fun with cfd

That's my next task.

It is fun, isn't it.

(I'm still worrying about all those error messages ...)

[oliveroxtoby]

But there were many error messages during the mesh install, and a few during the hisa install.

Unlikely to be anything to worry about - these are artifacts produced by OpenFOAM's build system. If dependency checker is happy, you are good to go.

[oliveroxtoby]

When using gmsh, the solver converges, when using cfmesh (2D-option)
the solver does not converge
everything depends on the mesh...

If the mesh resolution becomes fine enough, transient behaviour is picked up, preventing convergence of a steady solution. Adding turbulence modelling is a way around that.

[ljb]

After downloading the files you posted, I played with one for a while.

I found myself still having to 'fiddle' with things a lot, so I went back to your post and read it several times.

Finally I focused on this ...

When you load an existing case, most icons are greyed out. Doubleclick on
Cfd-Analysis in model-tree for activating them.

... since I remembered doing this on several different occasions, and having it NOT work.



I had your 'cfMesh' post loaded, and no cfd icons were active, so I gave it a try.

It did not work.

I tried several times. Then I fiddled with some other stuff, and tried again. Nope.

So I fiddled some more, no help. And fiddled some more ... and the damn icons turned on.

I had more or less stopped trying to follow a pattern with my fiddling, and did not keep an eye on the icons all the time.

So - I can not tell you which of my fiddles preceded the change in icon status.

Dang.

[ljb]

Thanks Oliver. I'll probably keep on worrying about those errors, but the little bit of experience I've had since installing the CFD package has convinced me that I can at least stop holding my fingers in my ears.

I am amazed that things like this are available for free.

And I am amazed that people like you and the others are willing to spend your time helping people like me.

When I get my Black Box working, and have a boat load of royalties filling my accounts, I WILL remember you guys.

Did I mention how amazed I am?

[ljb]

A new day.

When I quit for the night, I was still having trouble with inactive cfd icons (and alternate methods). No amount of fiddling worked.
This morning (after restarting), double clicking on the analysis branch of the tree works as advertised - icons go active.
*****************

Project Tree:
There are some differences between the window contents in the tutorial and what I see here in FC.
List of Final Properties -

Code: Select all

 tutorial lists: in1, in2, out, pipewalls, slipwalls 
    my FC lists: in1, in2, out, pipewalls, constraint, constraint001, Pad_Mesh

Analysis control dialog:
There are some differences between the window contents in the tutorial and what I see here in FC.

Code: Select all

 tutorial shows: a Working Directory label and text input box at top of dialog 
           next line down is CASE label followed by Write and Edit buttons
    my FC shows:  CASE label followed by Write and Edit buttons at top of dialog
           no Working-Directory-related controls

Otherwise the dialogs match.
The Edit button produces this msg in the status window:

Code: Select all

0.0: Please edit the case input files externally at: c:\users\lb17\appdata\local\temp\case

I'm guessing this is an outdated (or possibly premature?) tutorial screen. Should I move on?

[thschrader]

A new day.
Should I move on?

Sure. Patience is a virtue...

The constraint boundary can be used for 2D-meshing. Openfoam allways uses
a 3D geometry. In the tutorial you will see (take a very close look at the mesh on
page 14) that gmsh produces 2 layers of elements in the thin direction (the mesh-option
„from shape“ means, that gmsh detects if it is a 3D-solid or not, so in this case
it is and you get a 3D-mesh). You can suppress 3D-meshing by using the
constraint/2D bounding plane option (instead of wall/slip) for the outer walls.
cfmesh (or gmsh) then produces only one layer of elements in the thin direction.
The solver does not compute the solution of the navier-stokes-equation in the
1-layer direction. The solver „believes“ it is a 2D-problem.
This speeds up the calculation enormously.

BTW1:
In „view/panel“ activate the report-view window. Then you can see,
how the mesher fools you (when meshing complex geometry)

BTW2: I needed approx 200 hours of pure work to get a basic understanding
of openfoam. And I am still in beginner level.

Screenshots in zip.
Thomas

screens.zip

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