A one-dimensional Lagrangian model for large-volume mixing

In this paper, we describe the main features of a new Lagrangian model for mixing in large stably stratified enclosures. This new modeling approach el iminates artificial diffusion in strongly convectively dominated flows. The hyperbolic behavior of the system of PDEs requires a numerical method with no artificial diffusion to preserve the very strong gradients that can be present. We present the rudiments of the model and discuss an important asp ect of the discretization error analysis. The new BMIX code is first valida ted against an analytical model which has been shown to model experimental data very well. Finally, a comparison is presented against experimental dat a, gathered from a two-enclosure exchange flow set-up. Both comparisons sho w good agreement and verify the suitability of this new modeling approach a nd the correctness of the BMIX code. The computer code can simulate mixing in any stably stratified large enclosure containing a multi-component fluid . (C) 2001 Elsevier Science B.V. All rights reserved.