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Writing a step function in transient thermal problems

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Old   July 28, 2012, 15:56
Default Writing a step function in transient thermal problems
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Hi,

I've been trying to write a step function that makes my convection coefficient 0 every 6.4 seconds for a period of time of 0.3 secs. Other periods of time I want it to be 25.. I want this to continue indefinitely.

Anyone has ideas? Would really be glad if someone just wrote me the function..

Thanks
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Old   July 30, 2012, 05:59
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In fluent you could use a UDF which includes the following
Code:
double time;
double coeff;

time=RP_Get_Real("flow-time");
while(time > 6.7)
{
time = time-6.7;
}
if(time < 6.4) coeff = 25.0;
else coeff = 0.0;

Last edited by flotus1; July 30, 2012 at 06:24.
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Old   July 30, 2012, 06:46
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Hi and thanks for you feedback.

How should I input this kind of code?
I was meaning to use the "Functions" option under Define Loads..

Thanks again
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Old   July 30, 2012, 08:12
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So I see you are using the "transient thermal" node in Ansys workbench.
I don't know if it is possible there have this kind of boundary condition unless you write a table with the values for the whole simulation time.

Personally, I would rather use Fluent or CFX for a transient thermal analysis.
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Old   July 30, 2012, 08:23
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How can I write a table?

Thanks
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