[rupak504]

hi,

I want to define surface tension as a function of temperature using UDF at one of the interfaces, but the problem is, I have three interfaces in my problem. How to identify the interfaces?

regards

[AlexanderZ]

probably you are using VOF (volume of fluid) model for your simulation.
In that case you don't have predefined interface, so you should find it (usually interface is a bunch of cell with values of C_VOF between 0 and 1)
Once interface is defined you can apply whatever you want to that cells

[rupak504]

Originally Posted by AlexanderZ

probably you are using VOF (volume of fluid) model for your simulation.
In that case you don't have predefined interface, so you should find it (usually interface is a bunch of cell with values of C_VOF between 0 and 1)
Once interface is defined you can apply whatever you want to that cells

There are three phases, A,B and C. And i want to define surface tension between phase A and phase B as a function of temperature (Non-linear) rest others are constant. Normally i can use this

if (C_VOF(cell, A) != 0.0 && C_VOF(cell, A) != 1.0)

but since there will be 1 more interface (i.e. between phase A & phase C) where C_VOF of phase A lies between 0 and 1, it will employ the variable surface tension to that interface as well. Right?

[AlexanderZ]

unfortunately, I have no experience.
But it looks like you should use something like subdomain

Ansys Fluent Customization manual -> sub_domain_loop

I think, this is a way for you to switch between phases