boundary condition for scalar generation (scalarTransportFoam)
 

Hi,

I am doing simulation using the solver scalarTransportFoam, it solve the convection-diffusion equation for a passive transported scalar.
In the transportProperties file it is required a value for the diffusivity coefficient (DT)

I want to impose a generation of this scalar on a wall, precisely i want that every second a quantity X of the scalar enters the fluid domain.

The correct boundary condition is:

fixedGrandient with value = X/wall area; or with value = X/(wall area * DT) ?

I think is "X/(wall area * DT)" but a colleague told me to use "X/wall area"

or is there another more appropriate boundary condition?