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How are ambient properties implemented in COMSOL?

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I am looking through an existing Heat Transfer simulation modeled by someone else in COMSOL, and notice there is a section for "ambient properties". How are these implemented exactly? Are they somehow converted to flux boundary conditions? If so, what equations describe the implementation? If not, how do they work? They are clearly having some effect on my simulation results, so I'm curious how they work so I can express it mathematically. The "equation" drop down does not explain.



1 Reply Last Post 11 set 2023, 05:20 GMT-4
Anthony Paumier COMSOL Employee

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Posted: 1 year ago 11 set 2023, 05:20 GMT-4

Dear Alesanmi Odufisan,

I think this model has been made is much earlier version of COMSOL Multiphysics (maybe 5.3?). You can have information about ambient preoperties in the documentation (see https://doc.comsol.com/5.3/doc/com.comsol.help.heat/heat_ug_interfaces.08.12.html#645729 --- I am linking the documentation of version 5.3 since I think it will be the most appropriate for you). Basically the ambient properties section defines a number of variables that can be used in some features (see the documentation I linked above), but by default they do not have any effect if they are not used. An example of using ambient properties with the Temperature feature is to select "Ambient temperature" in the selectable input, or to keep it as "User defined" and enter "ht.T_amb". If ambient properties have an effect on your model, I suggest you look at the features and see which ones are set to "Ambient properties", or use "ht.xxx_amb" variables.

Best regards,

Anthony Paumier

Dear Alesanmi Odufisan, I think this model has been made is much earlier version of COMSOL Multiphysics (maybe 5.3?). You can have information about ambient preoperties in the documentation (see https://doc.comsol.com/5.3/doc/com.comsol.help.heat/heat_ug_interfaces.08.12.html#645729 --- I am linking the documentation of version 5.3 since I think it will be the most appropriate for you). Basically the ambient properties section defines a number of variables that can be used in some features (see the documentation I linked above), but by default they do not have any effect if they are not used. An example of using ambient properties with the Temperature feature is to select "Ambient temperature" in the selectable input, or to keep it as "User defined" and enter "ht.T_amb". If ambient properties have an effect on your model, I suggest you look at the features and see which ones are set to "Ambient properties", or use "ht.xxx_amb" variables. Best regards, Anthony Paumier

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