Neglect or include the boundary secondary gradients for diffusion and/or the interior secondary gradients at mesh faces.

On

Include both secondary gradients.

Off

Exclude both secondary gradients.

Interior Only

Include the interior secondary gradients only.

Boundaries Only

Include the boundary secondary gradients only.

The convection scheme to be used. For guidance on selecting a convection schemes, see Diffusion Term

1st-order

First-order convection scheme.

2nd-order

Second-order convection scheme.