about marangoni stress
 

Hello everyone:

I am modelling a selective laser melting process and we are consisting to add Marangoni stress in our momentum equation.

I saw there is a blank space(surface tension gradient) in the wall type boundary condition which I can enter a number.

According to the research, Marangoni stress not only happen on the wall but also on the interface. I am trying to add Marangoni stress with UDF, but don't have any idea how to write this code.

So I want to know how to make Marangoni stress acting right on the specified interface?

(I am using delta function to capture the interface)

can anyone help me to solve this problem?

Thank you