gas liquid flow
 

I am trying to modify gas liquid flow. The method is based on Eulerian and Eulerian model on CFX5.6 where water is treated as continuous and gas dispersed. The next step is that I want to change the drag coefficient at each time step. The drag coefficient will be expressed as a function of volume fraction of gas phase. Can any one give me some suggestions? Will CEL or Junction box work? Can any one send me a sample? Thanks