Dynamic Surface Tension
 

I am working on a problem involving the growth of bubbles in surfactant solutions, which exhibit a time-dependent surface tension behavior. How can I implement a similar temporal surface tension variation in interFOAM?
pEqn.H is the only place where sigma is used as SigmaK, which I am assuming comes from interfaceProperties. In the transportProperties, we specify only a constant sigma. How can I overcome this?

Write your own version of interfaceProperties.