volume fraction,mass fraction,bulk mass flow
 

"Hi! all friend I have a confusing problem when I try to set the value of "volume fraction" in the inlet condition fluid values tab for a gas-liquid two phase problem. If I give the value of volume fraction of different phase, what values should I give to the "Normal speed" of the two flow??are these values also apparent velocity or I should give a same velocity?? this problem confused me and I always give Mass flow rate for every flow.

by the way, when I select "Bulk Mass flow rate" in Boundary Details tab of inlet, I find the volume fraction in the fluid values tab means Mass fraction!(you can find this conclusion from the result file using CFX-POST).Is it true?? " Two questions above are cited from former messages which are just good for me.thanks for your reply!