A COMPARISON STUDY ON MULTIVARIANT AND UNIVARIANT FINITE-ELEMENTS FOR3-DIMENSIONAL INCOMPRESSIBLE VISCOUS FLOWS

In this paper, four quadratic hexahedron elements are considered and a ssessed for analysis of an incompressible viscous flow underlying the mixed finite element method. We classify the investigated elements as multivariant and univariant finite elements. With the same number of p ressure unknowns, multivariant elements are more constrained when the number of elements per side is larger than 10, as compared with that o f continous pressure elements. In multivariant elements, the coding is complicated by the appearance of restricted degrees of freedom at mid -face and mid-edge nodes. The comparison consequently should be mad vi a numerical example against the analytical problem.