The user function cs_user_saturne_coupling in cs_user_coupling.c is used to couple code_saturne with itself.
Such couplings allow explicit exchange of boundary conditions and source terms, possibly with different model choices in each domain.
In the case of a coupling between two code_saturne instances, first argument saturne_name of the function cs_sat_coupling_define is ignored. In case of multiple couplings, a coupling will be matched with available code_saturne instances based on that argument, which should match the directory name for the given coupled domain see examples.
The function usaste belongs to the module dedicated to external Fluid-Structure coupling with code_aster. Here one defines the boundary faces coupled with code_aster and the fluid forces components which are given to structural calculation. When using external coupling with code_aster, structure numbers necessarily need to be negative;
the references of coupled faces being (i.e. -1, -2), etc. For examples on the function we can see examples
1.14.0 