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

Summary A mixed finite element method for generalized convection-diffusion equations is proposed. The primitive variable with its spatial gradient and the diffusion flux are interpolated as independent variables. The variational (weak) form of the governing equations is given on the basis of the extended Hu-Washizu three-field variational principle. The mixed element is formulated with stabilized one point quadrature scheme and particularly implicit characteristic-based algorithm for eliminating spurious numerical oscillations. The numerical results illustrate good performances in accuracy and efficiency of the proposed mixed element in comparison with standard finite element.