Personalized heat source

Attia Benselama
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?!

7 Replies Last Post Jan 14, 2013, 11:16 AM EST
Posted: 5 years ago Jan 4, 2013, 5:35 AM EST
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
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

Attia Benselama
Posted: 5 years ago Jan 8, 2013, 9:08 AM EST
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 ?
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 ?

Magnus Ringh COMSOL Employee
Posted: 5 years ago Jan 8, 2013, 10:35 AM EST
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
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

Attia Benselama
Posted: 5 years ago Jan 10, 2013, 6:00 AM EST
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 ?!
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 ?!

Posted: 5 years ago Jan 10, 2013, 7:05 AM EST
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
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

Magnus Ringh COMSOL Employee
Posted: 5 years ago Jan 10, 2013, 7:25 AM EST
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
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

Attia Benselama
Posted: 5 years ago Jan 14, 2013, 11:16 AM EST
Updated: 2 months ago Aug 27, 2017, 2:44 PM EDT
Ok, thanks !
Ok, thanks !

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