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Interpolation Functions Units
Posted 07.01.2010, 18:10 GMT-5 1 Reply
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Hi,
I am trying to simulate a semiconductor using the AC\DC module with an applied electric field which in some areas is high (10^5 V/cm) and in some areas is low (10^2 V/cm). I wanted to model this by putting in interpolated data based on the drift velocity of electrons/holes at various electric fields and relate that to the conductivity of the subdomain.
Using Options-> Functions I defined a function named VelocityE. I then try to pass to it the magnitude of the electric field in the simulation (normE_emqvw), but it doesn't seem to like the fact that normE_emqvw isn't unitless. Is there a way to specify the units of the arguments and output of the function, or am I not using the tool properly?
Thanks,
Chris
I am trying to simulate a semiconductor using the AC\DC module with an applied electric field which in some areas is high (10^5 V/cm) and in some areas is low (10^2 V/cm). I wanted to model this by putting in interpolated data based on the drift velocity of electrons/holes at various electric fields and relate that to the conductivity of the subdomain.
Using Options-> Functions I defined a function named VelocityE. I then try to pass to it the magnitude of the electric field in the simulation (normE_emqvw), but it doesn't seem to like the fact that normE_emqvw isn't unitless. Is there a way to specify the units of the arguments and output of the function, or am I not using the tool properly?
Thanks,
Chris
1 Reply Last Post 10.01.2010, 05:12 GMT-5
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Posted:
1 decade ago
Hi
Units does not pass yet everywhere in COMSOL V3.5a, but its worth to render the variables "unitless" to avoid errors.
If you look at the function definition of ie.e materials data you will se many T[1/K] which means that T is first transformed into "Kelvin" from whatever units defined before (if none defined, Kelvin is the default I believe for the temperature) before rendered it unitless by dividing by "K". This is looked after by COMSOL.
So I would recommend that you should consider this systematically, when defining your variables and equations in the functions definitions too.
Try it out on simple cases first
Good luck
Ivar
Units does not pass yet everywhere in COMSOL V3.5a, but its worth to render the variables "unitless" to avoid errors.
If you look at the function definition of ie.e materials data you will se many T[1/K] which means that T is first transformed into "Kelvin" from whatever units defined before (if none defined, Kelvin is the default I believe for the temperature) before rendered it unitless by dividing by "K". This is looked after by COMSOL.
So I would recommend that you should consider this systematically, when defining your variables and equations in the functions definitions too.
Try it out on simple cases first
Good luck
Ivar