A variational formulation for convection-diffusion problems

A variational principle is proposed that under certain restrictions is shown to be equivalent to the advection-diffusion boundary value problem. Based on this variational principle, an upwind finite element method is derived that precludes spurious oscillations while possessing optimal convergence properties even in the multidimensional case. The formulation also points to a canonical choice of weighting functions for the Petrov-Galerkin method proposed by the Dundee and Swansea groups.