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Can the Initial Value (Temperature) be expressed using a function?
Posted Dec 4, 2011, 5:14 a.m. EST Heat Transfer & Phase Change, Studies & Solvers 2 Replies
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Hi, everyone,
I’m using the “heat transfer” module to construct my model. Traditionally, the ”Initial Value” node is only set into a constant value, usually 295.13 [K] or 300 [K]. I want to set the ”Initial Value” node into a function (external matlab function with the aid of Matlab or an analytic one in COMSOL), which means the initial temperature in the geometrical area is a function relative to the location(x, y).
For example, the initial temperature is a function and can be expressed as “293.15*x^2”, I defined a analytic function “an3= x^2”, so the expression in the initial value (temperature) tablet is set as “293.15[K]*an3(x[1/m])”. All are illustrated in Fig. 1, but it doesn’t work.
(photo is in the attachment)
Is there anyone can give me some tips and guidance? Could the “Initial Value” node finish (fulfill) this task?
(p.s. franking speaking, the example is simple, so there is no need to build an analytic function in global definitions)
Thanks sincerely in advance.
Best wishes to you and your family.
FM Huang
Dec. 4th.2011
I’m using the “heat transfer” module to construct my model. Traditionally, the ”Initial Value” node is only set into a constant value, usually 295.13 [K] or 300 [K]. I want to set the ”Initial Value” node into a function (external matlab function with the aid of Matlab or an analytic one in COMSOL), which means the initial temperature in the geometrical area is a function relative to the location(x, y).
For example, the initial temperature is a function and can be expressed as “293.15*x^2”, I defined a analytic function “an3= x^2”, so the expression in the initial value (temperature) tablet is set as “293.15[K]*an3(x[1/m])”. All are illustrated in Fig. 1, but it doesn’t work.
(photo is in the attachment)
Is there anyone can give me some tips and guidance? Could the “Initial Value” node finish (fulfill) this task?
(p.s. franking speaking, the example is simple, so there is no need to build an analytic function in global definitions)
Thanks sincerely in advance.
Best wishes to you and your family.
FM Huang
Dec. 4th.2011
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2 Replies Last Post May 31, 2012, 5:24 a.m. EDT
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Posted:
1 decade ago
Yes. Create your function in the function portion of the model tree. There is even a check box to specify that the function is a function of the spatial variables. Then refer to this same function in the initial values portion of the model tree. It is quite natural setup. Nothing special or fancy needed. If you prefer to use a MATLAB function, this can also be done as well, but not necessary.
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Posted:
1 decade ago
Good moorning Mr. James D. Freels
thanks for your post. I have a question: there is some problems to make a function where the variabiles are the coordinates? I will use this one for specifide initial values!
Thanks for your answere,
Simone
thanks for your post. I have a question: there is some problems to make a function where the variabiles are the coordinates? I will use this one for specifide initial values!
Thanks for your answere,
Simone