Outflow BC - Concentration gradient

Dear all,

I am using the Transport of Diluted Species physics.

Until now I have always used "outflow" as outlet boundary condition. This means that the gradient of the concentration, at the outlet section, is zero.

Someone knows if is it possible to set, at the outlet section, the same concentration gradient that there is at the nearest mesh nodes (instead of zero)?

Thank you very much.

Best Regards,

Francesca Messina