Natural convection through a hole in a vertical wall

Numerical methods and mathematical models of Elmer
kevinarden
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Re: Natural convection through a hole in a vertical wall

Post by kevinarden »

That looks very close, not sure you could get any better. If Boundary 2 does act as a hole, and it might if you don't assign any conditions to it, you could delete the boundary 2 elements from the boundary file and modify the header. BC 1 includes the interior wall but that may be OK depending on the assigned conditions.
foadsf
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Re: Natural convection through a hole in a vertical wall

Post by foadsf »

Kevin,

I still don't know how to write the Boundary Definitions section. Can you be kind to help me with that?

Best,
F.
foadsf
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Re: Natural convection through a hole in a vertical wall

Post by foadsf »

I think this should be the correct way to define the boundries:

Code: Select all

Boundary Definitions
!	type	out	int	double of the boundaries
	1		0	1	1
	2		0	2	1
	3		3	1	1
	4		4	2	1
End
Checked in ElmerGUI and seems to be OK.

Now moving to the .sif file.
Attachments
HoleNatConv.grd
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Last edited by foadsf on 02 Dec 2021, 13:29, edited 1 time in total.
kevinarden
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Re: Natural convection through a hole in a vertical wall

Post by kevinarden »

Mesh looks good
foadsf
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Re: Natural convection through a hole in a vertical wall

Post by foadsf »

the first attempt for the .sif file isn't that promising. Basically, everything is static. There is no convection!

Temperature distribution
Capture3.PNG
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HoleNatConv.sif
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Last edited by foadsf on 02 Dec 2021, 13:29, edited 1 time in total.
foadsf
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Re: Natural convection through a hole in a vertical wall

Post by foadsf »

Looking at Natural convection test examples, I see that I didn't have a Body Force:

Code: Select all

Body Force 1
  Name = "Bouancy"
  Boussinesq = True
End
I also added some other Material Properties:

Code: Select all

Material 1
! .....
  Reference Temperature = 300
  Heat expansion Coefficient = 3.43e-3
! .....
End
which I copied from here. Now I get the infamous error message:
...
350 0.4310E+01
351 0.4310E+01
ERROR:: IterSolve: Numerical Error: Too many iterations were needed.
STOP 1
Attachments
HoleNatConv.sif
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Last edited by foadsf on 02 Dec 2021, 13:29, edited 1 time in total.
kevinarden
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Re: Natural convection through a hole in a vertical wall

Post by kevinarden »

If I run it with air and the middle boundary at 303 I get a temp distribution
air.png
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case.sif
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kevinarden
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Re: Natural convection through a hole in a vertical wall

Post by kevinarden »

If I take the temperature boundary off the middle I get this
air.png
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foadsf
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Re: Natural convection through a hole in a vertical wall

Post by foadsf »

Kevin,

there must be a flow due to gravity/buoyancy leading to free convection. Is your case, also there is none. 😌
Last edited by foadsf on 02 Dec 2021, 13:28, edited 1 time in total.
kevinarden
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Re: Natural convection through a hole in a vertical wall

Post by kevinarden »

Sorry I did not have stokes turned on just the heat
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