Volume and boundary zones may be defined using the GUI, or through the cs_user_zones (in cs_user_zones.cpp).
Most zones may be defined in a simple manner using the general selection criteria, such as in the following example:
Or you can define 3 spherical source term zones based on geometrical criteria described by a rule.
More complex selections can be done by defining an appropriate selection function. For example, to select cells adjacent to boundary faces belonging to a group named "G3", the following selection function must first be defined:
It can then simply be used in a zone definition:
You can define simple boundary zones, allowing all faces not in the "INLET" or "OUTLET" groups to be considered as walls
Or simply allow overlapping for an existing zone: