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time dependent pressure BC on outlet

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Old   October 22, 2008, 08:05
Default time dependent pressure BC on outlet
  #1
sometimes1900
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Hi CFX user, i would like to set up a time dependent pressure boundary condition on the outlet, e.g. from 0-5s, pressure=0bar; from 5-10s, pressure=1bar; from 10-15s, pressure=0bar and so on. How can this Expression (CEL) be wroten? thank you for your reply in advance.
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Old   October 22, 2008, 10:13
Default Re: time dependent pressure BC on outlet
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Rogerio Fernandes Brito
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create (or define) an user function to input your time [s] and pression [N m^-2]. Make an 1D interpolation.

Arguments Units: [s]

Results Units: [N m^-2]

Interpolation Data -> Option -> One Dimensional

Create a name.txt file and build your data (time and pression using dot as your decimal separator).

After that, choose your pression as name(t) as your boundary condition, where t is the time in [s].
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Old   October 22, 2008, 11:16
Default Re: time dependent pressure BC on outlet
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sometimes1900
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Hi Rogerio, thanx for your reply. As you describled, i have defined an user function (name: function 1) in PRE. But in the outlet window i can not find the user function. How can i put the user function to outlet BC? Best regards
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Old   October 22, 2008, 13:29
Default Re: time dependent pressure BC on outlet
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Rogerio Fernandes Brito
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put "function 1(t)" in the box for the outlet. Just it. Donīt use space, in the name of the function. Use: "function1(t)"
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Old   October 24, 2008, 11:14
Default Re: time dependent pressure BC on outlet
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Adam
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An easier way would be just to create a CEL expression and input that into the outlet
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