Personalized heat source

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Attia Benselama

Attia Benselama

January 4, 2013 9:05am UTC

Personalized heat source

Good morning everybody,

I am a novice in use of COMSOL, I want to simulate the propagation of heat through a material, sounds easy but my heat source is a surface defined by a matrix (every pixel is a source with its own magnitude),

I want to know if COMSOL can simulate this kind of source, and how?!

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Ivar Kjelberg

Ivar Kjelberg

January 4, 2013 10:35am UTC in response to Attia Benselama

Re: Personalized heat source

Hi

check the Forum on importing an interpolation function "Data source Files with "Use Space coordinates as arguments", then apply this interpolation function into your BC entries.

--
Good luck
Ivar

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Attia Benselama

Attia Benselama

January 8, 2013 2:08pm UTC in response to Ivar Kjelberg

Re: Personalized heat source

Hi,

Thank you very much,
With some standing back I see that my request was "basic"!
Now I have an other question, to define my function I need to export data from matlab, witch are defined on a certain variation range, how can I indicate to COMSOL that my function is equal to 0 out that range ?

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Magnus Ringh

Magnus Ringh
COMSOL Employee
Sweden

January 8, 2013 3:35pm UTC in response to Attia Benselama

Re: Personalized heat source

Hi,

In the Interpolation function's settings window, under "Interpolation and Extrapolation", choose "Specific value" from the Extrapolation list. The default for "Value outside range" is 0, so that should give you the desired behavior.

Best regards,
Magnus Ringh
COMSOL

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Attia Benselama

Attia Benselama

January 10, 2013 11:00am UTC in response to Magnus Ringh

Re: Personalized heat source

Hi,
That's exactly what I want, thanks,
When i enter my function in heat source, it becomes orange, telling me that the unit given not expected, depite I didn't define any unit neither in my folder nor in the expression of my function, any idea ?!

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Ivar Kjelberg

Ivar Kjelberg

January 10, 2013 12:05pm UTC in response to Attia Benselama

Re: Personalized heat source

Hi

COMSOL might apply default units, check your "physics node", most operators are to be made unit-less. Anyhow "orange" is a warning no error it solves anyhow, but there might be a conversion and numerical scaling issue

x,y,z and t have default units I believe

--
Good luck
Ivar

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Magnus Ringh

Magnus Ringh
COMSOL Employee
Sweden

January 10, 2013 12:25pm UTC in response to Attia Benselama

Re: Personalized heat source

Hi,

My guess is that you have not assigned units to the input argument and function output in the Units section of the Interpolation function. Using

Arguments: K
Function: W/m^3

defines an interpolation function where the heat source values (W/m^3) are functions of the temperature (K).

If you want to treat the interpolation function as a unitless function, you need to "de-dimensionalize" the temperature variable used as argument when calling the function using unit syntax: T[1/K]

Best regards,
Magnus Ringh, COMSOL

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Attia Benselama

Attia Benselama

January 14, 2013 4:16pm UTC in response to Magnus Ringh

Re: Personalized heat source

Hi,

I think you are right, but I can't find any "units section of the Interpolation function" to assign units of input argument and output,
where is it exactly ?!

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