Elmer Discussion Forum

Hello alltogether,

I am frequently using extra Options to Control specialities of the solvers and normally, the entries in the Free Text fields in the GUI dialogues Show up in the SIF file at the end of the respective section. In one case however, that is the solver Control of the Navier-Stokes solver, the System just ignores entries in the free text field. The attached screenshot Shows such an entry. This behaviour can be repeated and does not Change. I am using Version: 8.2 (Rev: Release, Compiled: 2016-03-15) in a virtual machine running Windows 7 Enterprise, Version 6.1.7601 Service Pack 1 Build 7601.
I have seen similar types of requests here in the Reports for the GUI not creating the SIF correctly; as I understood they were normally small Jobs to fix - I hope this is the same here and do thank you for your Support!

Regards, Thomas.

Hi

The keywords may be roughly divided into Module-specific keywords, and ElmerSolver library keywords. Whether the library features work with given module is not self-evident.

In this case you try to use soft limiters for the MeshUpdate module. In addition to these keywords there should be either Upper or Lower "Mesh Update" values defined. Even then I'm not totally sure that it you can apply soft limiters to this equation. I would rather need to see a small unit test on that.

The use cases for soft limiters could be related to elasticity where you can create a contact condition for contact surface of given form, or in heat equation you can limit your upper temperature to be melting temperature etc. MeshUpdate solver is intended to continue deformations of solids into fluids and my imagination fails me here to see what soft limiters would be used in this case.

-Peter

Hi Peter,

thank you for your always quick Reply. I knew I forgot to mention something. The soft limiter functionality will Limit pressure to vapour pressure in a fluid film, hence it is given in the N-S solver. It is added as Body force to the fluid, the shown entry in the free text field just should Switch on limiter functionality in N-S solver.

But apart from the Simulation target at all, as I also recognized that "whatever" is entered in the free text fields, it is showing up in the SIF, I just realized it is NOT working with this one free text field in the N-S solver Control dialogue. One time even the solver denied starting, because I accidentally typed into another free text field some characters meant for another program in the Background, not realizing the current Cursor Focus was on the GUI dialogue. And ElmerGUI just trustingly transmitted the weird entry into the SIF file, where the solver then complained about it.

So at least something should Show up in the SIF file, when entered in the General Solver Control free text entry in N-S solver Control dialogue, wouldn't you agree?

BR, Thomas.

Yes, I agree that the free text should pop up on the sif file. Now whether it results to desired operation is another story. -Peter

Alright, Peter,
I completely agree - the operational results are also not proper Focus for a bug Report. So would you consider the described behaviour as something that can and should be corrected in the next Releases ? Otherwise we have to live with manually editing the SIF file every time after saving the project, which is quite tedious...

Best Regards,
Thomas.

Hi alltogether,

I just noticed another Twist to the whole Story. I was running my current Project without the MeshUpdate Solver active. In this case, the solver variables for the NS solver Change. The variable field now states the Solution variables "Flow Solution[Velocity:cdim Pressure:1]".

And the interesting fact: now the free text field entries get written into the SIF File. It seems somehow to be connected to the use of the mesh update solver ... (?)

Maybe this observations helps in Fixing this inconsistency,
Thomas.

Hello and good evening,

another, probably last update to this Topic. After rebuilding the Simulation case from scratch, the entries for "Procedure" and "Variable" in the NS solver Control Dialogue do not look like in the error case any more, although now MeshUpdate is also activated. Instead of previously

Procedure: "MeshSolve" "MeshSolver"
Variable: Mesh Update(cdim)

the entries now read like

Procedure: "FlowSolve" "FlowSolver"
Variable: Flow Solution[Velocity:cdim Pressure:1]

With the latter entries, the Statements in the free text entry field of the NS solver get flawlessly applied. In my suspicion, this is a rarely occurring screw-up by ElmerGUI. Definitely it will be hard to reconstruct. A Workaround for anyone facing similar issues is to rebuild the Simulation case completely fresh.

So far the concluding update from my side,
have fun with Elmer!
Thomas.