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Setting Initial Conditions

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Old   September 11, 2012, 17:21
Default Setting Initial Conditions
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Akim Faisal
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Hi,

I have a rectangular 2D channel flow and would like to set an initial condition of V=0 m/s at t=0 second and at t>0 V=2 m/s. Is there a way to do this in FLUENT version 12 without UDF?

Thanks for your help,
Akim
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Old   September 12, 2012, 02:27
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Daniele
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Hi, yes, you can use profiles, but you can't have a step change..I know this is possibile with udf..
See also this post:
transient profile-time step

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Old   September 12, 2012, 05:57
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Zhi-Gang Zhai
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you could use UDF to do it. CURRENT_TIME macro could get the time.
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Old   September 12, 2012, 06:05
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Quote:
Originally Posted by Akim679 View Post
Hi,

I have a rectangular 2D channel flow and would like to set an initial condition of V=0 m/s at t=0 second and at t>0 V=2 m/s. Is there a way to do this in FLUENT version 12 without UDF?

Thanks for your help,
Akim
Also if you want a step change there's no need to change velocity;
start your simulation with v=2 m/s; but if you want a linear change in velocity from t=0 till t=? s you can use profile or udf as suggested.
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Old   September 12, 2012, 08:31
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Can's you just initialize at 0 m/s, run the model steady state, and then switch to transient mode?

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Old   September 12, 2012, 12:49
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You could also do this with a Profile. Start your data with t=0, V=0 and then increment it however you'd like. Fluent will linearly interpolate between the data that you give it so if you want a step jump then it may not work.
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