anisotropic thermal conductivity

General discussion about Elmer

anisotropic thermal conductivity

Postby gsw_001 » 31 Mar 2010, 03:00

HI

I have been unsuccessfully trying to input orthotropic 2D thermal conductivities into the heat equation model.

I thought this was supported in Elmer based on the discussion of Model 1 - Heat Equation where it says that "For solids, conduction may be anisotropic and the conductivity a tensor"

I followed the Tutorial 10 approach for an anisotropic Youngs modulus on page 50 to no avail. A result from one of my many attempts is given below:

Excerpt from the SIF file:

Material 1
Name = "solid"

Density = 1550
Heat Capacity = 1450
Heat Conductivity
size 2 2
real 0.1 0.6
0.6 0.1
end
End



Elmer tells me:

Error:: Model Input:
Error:: Model Input: Unknown specifier: [end]
Error:: Model Input: In Section: [material 1]
Error:: Model Input: For propert name: [0.6 0.1]


Is it possible to have solve a solids heat conduction problem with anisotropic thermal conductivity using Elmer?
If so, can you please explain how to do it?

thanks

gsw
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Re: anisotropic thermal conductivity

Postby eraikkon » 22 Jul 2010, 18:18

I would also be very interested in the answer.
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Re: anisotropic thermal conductivity

Postby raback » 23 Jul 2010, 22:27

Hi

I think that the expression for heat conductivity is missing a line feed between the two rows. In fact you can have all the entries on the same row, the size decleration alone decleares the size, not the layout of the numbers. I would try with the following:
Code: Select all
Heat Conductivity(2,2) = Real 0.1 0.6 \
                              0.6 0.1

or as the variabletype is known a priori simply
Code: Select all
Heat Conductivity(2,2) = 0.1 0.6 0.6 0.1

-Peter
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Re: anisotropic thermal conductivity

Postby tacojoi » 01 May 2011, 14:56

Hi,
According to the above view, I think

(a) If I have a 2D model, kx = 1.0 & ky = 0.0, so
Heat conductivity(2,2) = Real 1.0 0.0 0.0 0.0

(b) Same as (a), kx = 0.0 & ky = 1.0, so
Heat conductivity(2,2) = Real 0.0 0.0 0.0 1.0

(c) If I have a 3D model, kx = 0, ky = 0 & kz=1.0, so
Heat conductitvity(3,3) = Real 0.0 0.0 0.0 0.0 0.0 1.0

Is that correct?
Please help me to confirm.

BR,
Taco.
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Re: anisotropic thermal conductivity

Postby raback » 01 May 2011, 15:34

Yep, except in 3D you need 9 components, not six. -Peter
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Re: anisotropic thermal conductivity

Postby tacojoi » 01 May 2011, 18:34

Hi, Peter,

Thanks a lot.

Taco
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Re: anisotropic thermal conductivity

Postby annier » 09 Sep 2017, 07:50

Hi,
Seeing the much relevance of anisotropic heat conduction in solids, I am trying to refresh this discussion started 7 years ago.
2D Model
kx = 0, ky = 1.0, so
Code: Select all
Heat conductitvity(2,2) = Real 0.0 0.0  0.0 1.0

3D Model
kx =1. 0, ky = 5.0 & kz=1.50, so
Code: Select all
Heat conductitvity(3,3) = Real 1.0 0.0 0.0 0.0 5.0 0.0 0.0 0.0 1.50


Yours Sincerely,
Anil Kunwar
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Re: anisotropic thermal conductivity

Postby annier » 13 Sep 2017, 12:38

Hi All,
Is it possible to vary the anisotropic material property with coordinates in Elmer?
Relevant threads:
1. viewtopic.php?f=3&t=3139&start=0&hilit=tensor+variable
2. viewtopic.php?f=7&t=2267&start=0&hilit=user+subroutine

Variation of a tensor with Coordinate
1.viewtopic.php?f=3&t=3802&start=0&hilit=tensor+matc
2. viewtopic.php?f=3&t=110 (length limit of matc)


Yours Sincerely,
Anil Kunwar
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