Third order nodal finite element methods with transverse and reduced integration for elliptic problems

This paper describes a solution technique for multidimensional elliptic problems based on the use of some third order nodal finite elements and on a reduction of the basic (multidimensional) problem to a set of coupled one-dimensional problems. This solution technique, developed rather heuristically in the framework of nuclear reactor computations in conjunction with early nodal methods, gets on a much firmer ground when applied with nodal finite elements. The first part of the paper deals with the general context of variational nodal finite element methods. The so-called "Transverse and Reduced Integration Method" is then described in the second part of the paper. Its numerical properties are illustrated by some examples.