transient boundary conditions

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transient boundary conditions

Postby 1234hoedjevanpapier » 05 Feb 2010, 16:59

Hi all,

I was wondering if it is possible to define time-dependent boundary conditions (for example temperatures or heat fluxes) in ElmerGUI? Is it also possible to read time-dependent profiles from textfiles?

thanks for your help.

regards,

Jeroen
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Re: transient boundary conditions

Postby 1234hoedjevanpapier » 08 Feb 2010, 02:27

Dear elmer team,

I found out that the 'scanning' mode can be used to define time dependent boundary conditions? I ran a test case, but thus far the temperature boundary does not change. I added a profile for boundary condition 3 with the following code, similar to a previous post http://www.elmerfem.org/forum/viewtopic.php?f=3&t=274&p=928&hilit=scanning#p928:
Code: Select all
Boundary Condition 3
  Target Boundaries(1) = 3
  Name = "Time_boundary"
  Temperature = Variable Time
  Real
0 266.65
1 266.05
2 265.85
3 265.45
4 265.25
5 265.05
6 264.85
7 264.55
8 264.65
9 265.25
10 266.45
11 267.25
12 268.15
13 268.75
14 269.15
15 269.25
16 269.45
17 268.75
18 269.15
19 269.75
20 269.65
21 269.75
22 270.05
23 269.95
  End
End


the first column is the time step, the second the corresponding temperature. But when postprocessing, the temperatures on boundary 3 do not correspond to the profile I defined/ don't change with time. I put the case in the attachment. What am I doing wrong?

thanks for your help,

Jeroen
test.zip
input file and mesh
(17.12 KiB) Downloaded 117 times
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Re: transient boundary conditions

Postby raback » 08 Feb 2010, 14:17

Hi Jaroen

As you have a real dependence on time you should use "Simulation Type" "transient" ("scanning" is intended for doing a number os steady state simulations varying some parameters). Then you can have your BCs depend on "time" in three different ways: table, MATC expression, UDF. For more examples look for instance http://www.nic.funet.fi/pub/sci/physics ... Manual.pdf p. 10-12 or search this site for "MATC".

The table may be included from an extarnal file using the following syntax:
Code: Select all
Temperature = Variable Coordinate 1
    Real
      include tprof.dat
    End

-Peter
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Re: transient boundary conditions

Postby annier » 22 Dec 2013, 17:24

Hi Peter,
It means the file with filename tprof.dat should be in the same directory with SIF file for the convenience.
Yours
Annier
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Re: transient boundary conditions

Postby cru2323 » 06 Dec 2017, 10:01

I'm looking to do HF Aviation monitoring and scanning of frequencies in memory. I'm used to hardware units such as an R75, which are no longer made. Will SDRPlay be able to be used for HF monitoring and scanning? I'm very unfamiliar with how the software works. Thanks for the help.
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