Boundary Condition for bifurcation: outflow-pressure
 

Dear all,
I am not very experienced in setting Boundary Conditions for the simulation of blood flow through a vessel bifurcation of the coronary arteries and have some questions concerning this:
I want to simulate a species transport (mixture) and therefore I am not allowed to set the outflow (flow rate of the vessel branches) as BC for this case. I planned to estimate the flow rate of the two vessel branches via a scaling law and do a simulation without species to get the pressure at both outlets and use these pressures as BC for the real simulations. Does somebody have experience with this and can let me know whether this procedure is usual for this case? It seems to be pretty inaccurate to me. Furthermore I don’t know whether I should set the pressure distribution at the outlet cross-section area as BC or just a constant averaged value for the whole cross-section.
It would be really nice, if somebody give me some advice!
Thanks a million in advance!
Lilly