Search found 28 matches

by Saint
31 May 2023, 05:03
Forum: General
Topic: Boundary treathment in multi-body sim + radiation
Replies: 3
Views: 385

Re: Boundary treathment in multi-body sim + radiation

1. Thanks for pointing out the mesh issue ! My first goal was to have 3 distinguished parts, so I can give them different materials. I wonder how I can have 3 parts, but with shared boundaries!??!?!..... I use FreeCAD and Gmsh and my go-to option was the "compound function" in FC... now I ...
by Saint
30 May 2023, 17:22
Forum: General
Topic: Boundary treathment in multi-body sim + radiation
Replies: 3
Views: 385

Boundary treathment in multi-body sim + radiation

Hello again, First of all thank you for your patient, I know I have asked so many basic questions; I hope you can guide me as before: I am simulating a hot object, inside a box; the bot T is fixed and constant, but the air T and the object T can change. My goal is to simulate and calculate the T and...
by Saint
24 May 2023, 21:40
Forum: General
Topic: Radiation ("warning: property request") + Boundary Treatment
Replies: 6
Views: 742

Re: Radiation ("warning: property request") + Boundary Treatment

Hi To original questions 1) yes 2) Dirichlet fixes the temperature and overruns everything else. Open boundary means that view factors will not be normalized to 2Pi. As they sum of to less the rest is assumed to be idealized radiation. 3) No. Heat gap is intended to jumps. All PDEs are by default c...
by Saint
24 May 2023, 21:20
Forum: General
Topic: Tips and tricks!?
Replies: 3
Views: 480

Re: Tips and tricks!?

Hi I think one issue here is that most of us use Elmer almost exclusively on Linux. This is also the natural platform for supercomputing so if you want to got to larger problems things will be almost the same. The parallel computing of Elmer has been touched in webinar series, the slides are here h...
by Saint
24 May 2023, 20:58
Forum: General
Topic: Compressiblity (in rooms's air simulation) + Data Validation
Replies: 10
Views: 760

Re: Compressiblity (in rooms's air simulation) + Data Validation

Do not put "emissivity" for air. It does not make any sense. Air cannot have emissivity since it cannot have a surface. The radiating material should have emissivity defined. The direction of the normal vector will be set from the material that has emissivity defined outwards. For this re...
by Saint
22 May 2023, 19:55
Forum: General
Topic: Compressiblity (in rooms's air simulation) + Data Validation
Replies: 10
Views: 760

Re: Compressiblity (in rooms's air simulation) + Data Validation

Thank you again ! Just remembered another question: Assuming, my understanding in last post is correct: "Air, is usually considered as incompressible in low speeds, but if I want to apply a compressibility model, then the "thermal" model is the correct choice" :?: Should I use th...
by Saint
22 May 2023, 19:51
Forum: General
Topic: Radiation ("warning: property request") + Boundary Treatment
Replies: 6
Views: 742

Re: Radiation ("warning: property request") + Boundary Treatment

The body force creates heat in the entire body. If heat is just one surface you should use boundary conditions. The heat at a boundary will conduct to any body that is attached to that boundary. You can fix the temperature of the box at its boundaries using the boundary conditions. But if there is ...
by Saint
22 May 2023, 19:33
Forum: General
Topic: Compressiblity (in rooms's air simulation) + Data Validation
Replies: 10
Views: 760

Re: Compressiblity (in rooms's air simulation) + Data Validation

Thanks,

So, to verify my simulation, I need to compare it with experimental data.

But as for validation, it returns to the code and the mathematical process... I don't know if it is expected from me or is it something very advanced and only expected in programming level?
by Saint
22 May 2023, 18:50
Forum: General
Topic: Compressiblity (in rooms's air simulation) + Data Validation
Replies: 10
Views: 760

Re: Compressiblity (in rooms's air simulation) + Data Validation

Just remembered another question: Assuming, my understanding in last post is correct: "Air, is usually considered as incompressible in low speeds, but if I want to apply a compressibility model, then the "thermal" model is the correct choice" :?: Should I use the compressibility ...
by Saint
22 May 2023, 18:13
Forum: General
Topic: Tips and tricks!?
Replies: 3
Views: 480

Re: Tips and tricks!?

honestly, I was expecting a heated conversation for this topic. I believe it is safe to assume most people are using linux, therefore no one has any points to add.

Maybe, administrators might want to delete this topic; since there is no useful post in it.