Mixed finite element method for generalized convection-diffusion equations based on implicit characteristic-based algorithm

A mixed finite element method for generalized convection-diffusion equationsis proposed. The primitive variable with its spatial gradient and thediffusion flux are interpolated as independent variables. The variational(weak) form of the governing equations is given on the basis of the extendedHu-Washizu three-field variational principle. The mixed element isformulated with stabilized one point quadrature scheme and particularlyimplicit characteristic-based algorithm for eliminating spurious numericaloscillations. The numerical results show good performances in accuracyand efficiency of the proposed mixed element in comparison with a standardfinite element.