Boundary condition variable with time

marsa27 · April 7, 2020, 06:00

Hi, I'm interested to set a variable velocity boundary condition with the time in an unsteady simulation. Is it possible in CFX? In particular I would to fix a velocity linearly increasing like V=6*t [m/s].
According to me I could set an expression for the coefficient: a=6 [m*s^-2] and a new expression called vel=a*Time, then to put as velocity boundary condition the expression Vel... is it correct?

Gert-Jan · April 7, 2020, 06:28

If you define the equation in Pre, you have the option to plot it as function of time. This should give you more than enough confidence.

marsa27 · April 7, 2020, 06:41

Quote:

Originally Posted by Gert-Jan

If you define the equation in Pre, you have the option to plot it as function of time. This should give you more than enough confidence.

Yes it is correct. Thank you

April 7, 2020, 06:00	Boundary condition variable with time	#1
marsa27 Senior Member Davide Join Date: Jul 2015 Posts: 107 Rep Power: 10	Hi, I'm interested to set a variable velocity boundary condition with the time in an unsteady simulation. Is it possible in CFX? In particular I would to fix a velocity linearly increasing like V=6t [m/s]. According to me I could set an expression for the coefficient: a=6 [ms^-2] and a new expression called vel=a*Time, then to put as velocity boundary condition the expression Vel... is it correct?

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April 7, 2020, 06:28		#2
Gert-Jan Senior Member Gert-Jan Join Date: Oct 2012 Location: Europe Posts: 1,836 Rep Power: 27	If you define the equation in Pre, you have the option to plot it as function of time. This should give you more than enough confidence.