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-   -   Oscillatory buondary condition (http://www.cfd-online.com/Forums/star-ccm/85483-oscillatory-buondary-condition.html)

MarcoB February 27, 2011 09:24

Oscillatory buondary condition
 
Hi everyone,

I've got to impose an oscillatory boundary condition across a conduit (e.g. a pressure outlet). So my function will be as 10Pa*sin(100*t) where t is time.

I don't know how to write my function down the software.

Could anyone help?

Regards

Marco

Vinicius February 28, 2011 09:16

Hi Marco,

In the Field functions node, create a new one and in the description, set this: 10*sin(100*$Time)

Regards,

Vinicius

MarcoB March 2, 2011 11:58

Thank you so much Vinicius, you've really been very helpful!!

I'll ask you another question, I know it could be trivial but unfortunately I'm just a beginner:

seen I'm performing an unsteady simulation, I bet I'll have a transitional and then an oscillatory regime, so I got to set the time of duration of the simulation, say it is 30 seconds, the time step, say it is 0,1 sec and the iterations per time step, say 50; is it right? Where should I give these values?

Thanks again

Regards

Marco

Vinicius March 2, 2011 12:42

The Time-Step is defined in the solver node -> Implicity Unsteady solver, in its properties.

The Maximum Physical Time and the Maximum Inner iterations are defined in the stopping criteria node. Donīt forget to make inactive the maximum steps criteria....

Regards,

Vinicius

MarcoB March 2, 2011 16:38

Thanks a lot! You've been very helpful!

Regards

Marco

Henry Arrigo March 2, 2011 17:07

Hello all,
I v same the same problem as Marco has. I want to impose a sinusoidal force on a body. In the external force node there is no possibility to bind a Field function. What s your suggestion please?
thank you all.


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