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Time dependent surface concentration?
Posted May 24, 2012, 5:06 p.m. EDT Version 4.2a 2 Replies
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Hi All
I'm trying to test a cylindrical model against an analytical solution for a simple diffusion model and would like the surface concentration of one of the variables to be a ramp. I generate a ramp function but can't use a boundary condition for a variable like:
1e-6*ramp1
Its displayed in red and the Jacobian can't be evaluated. How can I make the surface concentration a function of time?
Many thanks for your help with this steep learning curve...
Mark
I'm trying to test a cylindrical model against an analytical solution for a simple diffusion model and would like the surface concentration of one of the variables to be a ramp. I generate a ramp function but can't use a boundary condition for a variable like:
1e-6*ramp1
Its displayed in red and the Jacobian can't be evaluated. How can I make the surface concentration a function of time?
Many thanks for your help with this steep learning curve...
Mark
2 Replies Last Post May 25, 2012, 10:34 a.m. EDT
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Posted:
1 decade ago
Hi
your ramp1() is an operator you need to define a variable to drive the ramp.
Either you have a defined "Parameter" ie Param, and you adapt Param from the steady state solver continuation tab
then you write
1e-6[your_units]*ramp1(Param)
or you have a time dependent analysis, in which case you use t in seconds to drive your ramp opertor with a
1e-6[your_units]*ramp1(t[1/s])
the t[1/s] is to remove any units and use a time stepping in seconds as operators do not expect units as arguments
--
Good luck
Ivar
your ramp1() is an operator you need to define a variable to drive the ramp.
Either you have a defined "Parameter" ie Param, and you adapt Param from the steady state solver continuation tab
then you write
1e-6[your_units]*ramp1(Param)
or you have a time dependent analysis, in which case you use t in seconds to drive your ramp opertor with a
1e-6[your_units]*ramp1(t[1/s])
the t[1/s] is to remove any units and use a time stepping in seconds as operators do not expect units as arguments
--
Good luck
Ivar
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Posted:
1 decade ago
Many thanks, that seemed to do it. Now I've to try to understand why point graphs don't adopt the new integration interval etc...
Cheers Mark
Cheers Mark