Support needed regarding Boundary Conditions.

Schurl · January 17, 2018, 07:08

Hi All,

I am Really struggling to choose the right BC.
I have to state, that i last worked with CFD 15 Years ago at the university using StarCD and icem.

I can handle in principle Navier-Stokes EQ but i am not able to derive alle the turbulence models behind openFOAM especially using sonicFoam.

I remember with StarCD i just had to define surfaces and apply BC like pressure or velocity at inlet, ambient pressure at outlets, walls wheter as no slip or symmetry.

Now have to define the BC in approx. 7 files where i honestly copy and paste the BC from the tutorials with a lot of except p and u.

As i turned now from given inlet velocity to high pressure at the inlet it does not work anymore and i am lost in all those files k, epsilon etc.

Does someone has an overview of usual BC for a specific solver like sonicFoam? The should be always same or?

Thanks in advance
Georg

Tosbaga · January 17, 2018, 17:06

Hello this link can be usefull to you

https://www.openfoam.com/documentati...conditions.php

Regards

Schurl · January 19, 2018, 15:56

Hi,

thanks, but I knew this link already.
My problem is, what i should use for sonicFoam for just a simple channel for example: Inlet-outlet-walls, where at the inlet is 1.01 bar, at the outlet 1bar.

I have to define BC for
- T
- U
- P
- alphat
- epsilon
- k
- nut

Here I am lost. I use the ones from other examples, but the results are unfortunatel unplausible.

Kind regards
George

January 17, 2018, 07:08	Support needed regarding Boundary Conditions.	#1
Schurl New Member Georg Join Date: Dec 2017 Posts: 15 Rep Power: 8	Hi All, I am Really struggling to choose the right BC. I have to state, that i last worked with CFD 15 Years ago at the university using StarCD and icem. I can handle in principle Navier-Stokes EQ but i am not able to derive alle the turbulence models behind openFOAM especially using sonicFoam. I remember with StarCD i just had to define surfaces and apply BC like pressure or velocity at inlet, ambient pressure at outlets, walls wheter as no slip or symmetry. Now have to define the BC in approx. 7 files where i honestly copy and paste the BC from the tutorials with a lot of except p and u. As i turned now from given inlet velocity to high pressure at the inlet it does not work anymore and i am lost in all those files k, epsilon etc. Does someone has an overview of usual BC for a specific solver like sonicFoam? The should be always same or? Thanks in advance Georg

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January 17, 2018, 17:06		#2
Tosbaga New Member Tosbaga Join Date: Mar 2017 Location: Earth Posts: 19 Rep Power: 9	Hello this link can be usefull to you https://www.openfoam.com/documentati...conditions.php Regards

January 19, 2018, 15:56		#3
Schurl New Member Georg Join Date: Dec 2017 Posts: 15 Rep Power: 8	Hi, thanks, but I knew this link already. My problem is, what i should use for sonicFoam for just a simple channel for example: Inlet-outlet-walls, where at the inlet is 1.01 bar, at the outlet 1bar. I have to define BC for - T - U - P - alphat - epsilon - k - nut Here I am lost. I use the ones from other examples, but the results are unfortunatel unplausible. Kind regards George