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Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

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Initial condition over a certain time

Posted 2016年4月7日 GMT-4 09:23 Heat Transfer & Phase Change, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.4 6 Replies

Maximilian Maußner
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Hello,
i have another problem with COMSOL and i don`t know if there is a solution for my idea of implementing.
Is there an opportunity to have an initial condition over a certain time? I want to simulate soldering by laser. Therefore the geometry of the solder is located on the top of the geometry of a metal plate. Now it would be great to have a condition, that defines the liquid temperature of the solder over a certain time. For example to have a temperature of 600 °C for 1 second. The standard initial condition only allows a temperature at the point of time of 0 seconds.
I have attached a jpeg with the geometry to show you.
It would be great if you can help me, again!
Thanks a lot!
With best regards,
Maximilian Maußner
6 Replies Last Post 2016年4月13日 GMT-4 03:31
Parth Swaroop
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Posted: 9 years ago 2016年4月8日 GMT-4 02:58
Is it possible to try this with user defined function? you could create a T=f(t), so your input argument is time (s) and output is K.
Is it possible to try this with user defined function? you could create a T=f(t), so your input argument is time (s) and output is K.
Maximilian Maußner
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Posted: 9 years ago 2016年4月8日 GMT-4 05:44
At first, thank you for the idea. But unfortunately, it is not running as desired.

I created an analytic function f with argument t. The unit of the argument is s and the unit of the function is K.
f(t) = value of temperature * rectangle function (t)
As parameters i have 0 s for the lower limit and 1 s for the upper limit.

The function is compiling as shown in the attached file.

When refering to the function in the initial condition, the function is written in yellow and there is a error message called unknown variable. You can also see this in another attached file.

Is there an opportunity to type a function into the temperature field of the initial condition?


At first, thank you for the idea. But unfortunately, it is not running as desired. I created an analytic function f with argument t. The unit of the argument is s and the unit of the function is K. f(t) = value of temperature * rectangle function (t) As parameters i have 0 s for the lower limit and 1 s for the upper limit. The function is compiling as shown in the attached file. When refering to the function in the initial condition, the function is written in yellow and there is a error message called unknown variable. You can also see this in another attached file. Is there an opportunity to type a function into the temperature field of the initial condition?
Lasse Murtomäki
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Posted: 9 years ago 2016年4月8日 GMT-4 07:07
You have to call the function an1(t), the argument explicitly involved.

Lasse
You have to call the function an1(t), the argument explicitly involved. Lasse
Maximilian Maußner
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Posted: 9 years ago 2016年4月8日 GMT-4 07:45
Thank you! Now it compiles. But the result doesn't change comparing to the "standard" initial condition. :(

Is there any other possibility to create an initial conditon for a certain time?

By the way, does anybody know why i sometimes get these incomplete graphics like in the attached file?
Thank you! Now it compiles. But the result doesn't change comparing to the "standard" initial condition. :( Is there any other possibility to create an initial conditon for a certain time? By the way, does anybody know why i sometimes get these incomplete graphics like in the attached file?

Attachments:

Lasse Murtomäki
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Posted: 9 years ago 2016年4月11日 GMT-4 01:46
If you have defined the plot range manually, values beyond the limits are not plotted and those areas remain white.

Lasse
If you have defined the plot range manually, values beyond the limits are not plotted and those areas remain white. Lasse
Maximilian Maußner
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Posted: 9 years ago 2016年4月13日 GMT-4 03:31
Thank you very much!
Thank you very much!

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