BC - set velocity and outlflow for MULTIPHASE
 

Hi! I need to write an UDF for the set-up of a boundary control in a multiphase flow (air + water). The boundary control is a free surface for the phase water which will have Vy=0 and Vx will be calculated by FLUENT. Additionally air passes through the boundary control and escapes to the atmosphere (water doesn't pass through), due to the difference of density between water and air. So, the idea is that this UDF will impose: - phase water: Vy=0 and Vx free - phase air: condition of pressure outlet or outflow

Has anyone had previous experiences writing an UDF like this? Any information welcome. Many thanks