unsteady species transport
 

I am simulating unsteady(pulsatile) laminar flow with species transport in a tube. I am implementing segregated solver with species transport selected in Fluent 6.1.

The problem I encountered is the species profile in the flow domain at different time steps I found them zero even if at inlet there is a well defined non zero species concentration.

The same problem for steady state case gives a reasonable result.

I wonder if there is some procedure missed in the unsteady simulation.