i use the vof model and species model. After obtaining the results of flow, i want to solve the species model in liquid phase(secondary phase) . By using the value of the volume of fraction, the interface position is determined. so the mass fraction of the cell at the interface is specified to be a constant of 0.7 by using the macro define_adjust. but from the post process the results of mass fraction at the interface is not 0.7, it is lower than 0.7. i have no idea. is there somebody know that? thanks in advance. is there some problems in my idea and set up?

can somebody help me?