Time-dependent BC's

doodek · December 25, 2010, 13:59

Hello,

I have a small problem with time dependent boundary conditions.
I would like to solve rotor-stator problem (periodic subsection). How to obtain change of rotational speed with time? For example: for 0-10 second rotational speed 1000 rpm, for 10-20 s rotational speed 20 000 rpm. I have the same problem with pressure in inlet boundary condition. How to simulate sudden pressure jump in inlet (for example after 5. second)?
I would be grateful for all suggestions.

Regards,
doodek

ghorrocks · December 25, 2010, 18:09

Use a CEL expression to define the rotational speed or pressure as functions of time. You can either use a 1D interpolation function or CEL functions. V12 or earlier you have to use the step() function, V13 you can use if/then statements.

December 25, 2010, 13:59	Time-dependent BC's	#1
doodek New Member Join Date: Oct 2009 Posts: 24 Rep Power: 17	Hello, I have a small problem with time dependent boundary conditions. I would like to solve rotor-stator problem (periodic subsection). How to obtain change of rotational speed with time? For example: for 0-10 second rotational speed 1000 rpm, for 10-20 s rotational speed 20 000 rpm. I have the same problem with pressure in inlet boundary condition. How to simulate sudden pressure jump in inlet (for example after 5. second)? I would be grateful for all suggestions. Regards, doodek

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December 25, 2010, 18:09		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	Use a CEL expression to define the rotational speed or pressure as functions of time. You can either use a 1D interpolation function or CEL functions. V12 or earlier you have to use the step() function, V13 you can use if/then statements.