Mass Transfer UDF using Fluent VOF
 

Hello,
I am studying air bubble dynamics from a submerged orifice in pool of aqueous soln of surfactants. As surfactant molecules adsorb and desorb on the moving bubble interface, I need to put a concentration boundary condn on the moving interface. (need to specify a specific concentration function on the bubble interface). As I am using VOF module in Fluent 12, my question is, can I specify a concentration BC on the moving bubble interface? How do I limit my concetration BC equation to region where volume fraction is between 0 to 1? Can I write a UDF for the same?