A Robin–Robin preconditioner for advection–diffusion equations with discontinuous coefficients Original Research Article

We consider an advection–diffusion problem with discontinuous viscosity coefficients. We apply a substructuring technique and we extend to the resulting Schur complement the Robin–Robin preconditioner used for problems with constant viscosity. A quasi optimal convergence analysis is performed in the case of uniform convection by means of Fourier techniques. The variational formulation in order to generalize the preconditioner to an arbitrary number of subdomains is also addressed, as well as some numerical tests in 3D.