hi

I have seen in Fluent manual in chaper 13.1.1 and in 13.1.5 about diffusion at inlet. This says

Diffusion at Inlets

For the segregated solver in FLUENT, the net transport of species at inlets consists of both convection and diffusion components. (For the coupled solvers, only the convection component is included.) The convection component is fixed by the inlet species mass fraction specified by you. The diffusion component, however, depends on the gradient of the computed species field at the inlet. Thus the diffusion component (and therefore the net inlet transport) is not specified a priori. See Section 13.1.5 for information about specifying the net inlet transport of species.

1. Since net transport of species at inlet differs from segregated to coupled solvers will it make any difference in the results. 2. What does the diffusion component at inlet means. 3. Where can I find more details of this. Any references. 4. How this is treated in discretized form at the inlet.

One more question. How to judge that the flow is convective dominent or diffusive dominant.

Thanks in advance Balaji

Convection and Diffusion dominance is judged by Peclet Number. If Peclet number is greater than 1 then it is convection dominant else diffusion dominant.

Vinod Dhiman