The Surface Reactions (sr) interface (
), found under the
Chemical Species Transport branch (
) when adding a physics interface, is used to model the chemical reactions of surface and bulk species on a boundary. Surface species can be transported in the tangential direction of the surface by Fick’s law whereas bulk species are assumed to be immobile on the surface.
When this physics interface is added, these default nodes are also added to the Model Builder—
Surface Properties,
No Flux, and
Initial Values. Then, from the
Physics toolbar, add other nodes that implement, for example, boundary conditions. You can also right-click
Surface Reactions to select physics features from the context menu.
The Label is the default physics interface name.
The Name is used primarily as a scope prefix for variables defined by the physics interface. Refer to such physics interface variables in expressions using the pattern
<name>.<variable_name>. In order to distinguish between variables belonging to different physics interfaces, the
name string must be unique. Only letters, numbers, and underscores (_) are permitted in the
Name field. The first character must be a letter.
The default Name (for the first physics interface in the model) is
sr.
Enter the Number of surface species. Use the
Add surface concentration (
) and
Remove surface concentration (
) buttons as needed. The same number of
Surface concentrations cs,
cs2,
cs3...are then listed in the table.
Enter the Number of bulk species. Use the
Add bulk concentration (
) and
Remove bulk concentration (
) buttons as needed. The same number of
Bulk concentrations cb,
cb2,
cb3...are then listed in the table.
By default the Compensate for boundary stretching check box is selected for the
Surface Properties node. This section is then used to stabilize the tangential mesh velocity term.
When the Compensate for boundary stretching check box is cleared (not selected), and for fixed geometries or moving geometries, the stabilization has no effect.
) and select 
) and select 