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-   -   pressure can be varied at different timestep ? (http://www.cfd-online.com/Forums/cfx/24280-pressure-can-varied-different-timestep.html)

SKARP July 18, 2007 08:39

pressure can be varied at different timestep ?
 
Hi,

I want to vary the pressure from 0-5 bar at the inlet by the time interval of 0-5 sec. How this can be possible ?

Omer July 18, 2007 12:51

Re: pressure can be varied at different timestep ?
 
Yes it is possible. If you have a function with respect to time, you can use the Expressions tab for this purpose.

SKARP July 19, 2007 00:14

Re: pressure can be varied at different timestep ?
 
Can u pls tell me the expression.I badly in need of it.

Robin July 19, 2007 09:41

Re: pressure can be varied at different timestep ?
 
Create a 1D function in Pre, say you call it myPressure. Enter coordinate units of [s] ) and result units of [Pa]. Enter coordinates and results for 0 [s], 0 [Pa] and 5 [s], 5 [Pa]. Turn on extend min and extend max. To use the function, enter the following expression in your boundary condition for pressure:

myPressure(t)

That's it.

Regards, Robin

SKARP July 20, 2007 02:02

Re: pressure can be varied at different timestep ?
 
Hi Robin,

Thanks a lot,I am not able to understand clearly Can u pls give it in expression format. That would be helpful to do my project successfully

I want to vary the pressure from 0-5 bar during the time intervel of 0-10 sec at inlet.

For every 2s the pressure should be varied.

Can u give it in expression format pls.

Robin July 20, 2007 15:39

Re: pressure can be varied at different timestep ?
 
Read the doc on 1D profiles. It should be fairly obvious how to do this.


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