transient boundary conditions

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1234hoedjevanpapier
Posts: 3
Joined: 05 Feb 2010, 16:56

transient boundary conditions

Post by 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

1234hoedjevanpapier
Posts: 3
Joined: 05 Feb 2010, 16:56

Re: transient boundary conditions

Post by 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 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 149 times

raback
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Re: transient boundary conditions

Post by 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

annier
Posts: 1102
Joined: 27 Aug 2013, 13:51
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Re: transient boundary conditions

Post by 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

cru2323
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Joined: 06 Dec 2017, 09:53
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Re: transient boundary conditions

Post by 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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