Hi
I'm a bit confused about which macro can be used to change the material property that is changing with temperature?, is it DEFINE_PROPERTY or DEFINE_ PROFILE?
I have found the thread (link) below which used DEFINE_PROFILE whereas there are some examples in ANSYS UDF manual use DEFINE_PROPERTY. Can anybody explain to me what is the difference?.
https://www.cfd-online.com/Forums/fluent-udf/139979-temp-dependent-emissivity-udf.html#post718649
In my model there are some boundaries (walls) that their emissiviy change with temperature. For example
for a specific wall at T=200 C emissivity = 0.80 T=400 C emissivity = 0.82 T=600 C emissivity = 0.84
How can I write the suitable UDF for this case? and which macro do I need to use?
Any help is much appreciated
Hello Oula Fatla,
DEFINE_PROPERTY is used when you want to modify materials property with some logics/conditions. Like the change in material properties with respect to time or temperature
DEFINE_ PROFILE is used when you want to modify boundary conditions like inlet velocity, the temperature of walls etc.
in your condition, you have to go for DEFINE_ PROFILE.
Steps for UDF:-
1) Read wall temperature using a loop.
2) Use if-else statement for condition
3) pass emissivity via argument
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