Reply To: Reverse flow problem

[SRP]

Hi,

It means species transport has an issue.

A very low species mass diffusivity can affect the convergence specially in regions with low turbulent diffusivity (viscosity). The diffusive part of the species transport equation can become extremely small compared to convective part and thus might create problems with convergence.

You can try to start with a higher laminar mass diffusivity for the species and then slowly drop it.