Verification of the stele code within the framework of the Chemval project

Phase 3 of the international CHEMVAL exercise has made it possible to devise verification tests for models coupling geochemistry and transport. The STELE model, built at the Centre d'Informatique Geologique, is a two-step coupled model, solving the geochemical and transport equations in two stages. The solution of two of the exercises from phase 3 of CHEMVAL is presented. One has an analytical solution which compares satisfactorily with the results of the calculation by STELE. The other raises numerical problems typical of a two-step algorithm. In its present state the STELE model is nevertheless a calculation tool well suited to systems with weak geochemical contrasts. Future development of STELE should mainly focus on the numerical aspects in order to extend the applicability of the model. 7 figs., 2 tabs., 9 refs