A multimesh adaptive scheme for air quality modeling with the finite element method
A multimesh adaptive scheme for convection–diffusion–reaction problems for a large number of components is presented. The problem is solved by splitting transport and reaction processes. This way, the evaluation of the nonreactive part for each component and the reaction at each node constitute independent tasks. This allows to discretize each component of the solution on a distinct computational mesh, adapted on the basis of its error indicator. The standard single-mesh strategy is used for comparison. Simulations of a point emis- sion in a 3D domain are presented. Low remeshing periods of the adaptive scheme are found to be optimal, in terms of computational cost and accuracy, for the nonreactive problem. Examples with several reaction terms, with an increase of the complexity, are then presented. Results show that the accuracy of single-mesh and multimesh strategies are similar. Instead, the computational cost of the multimesh strategy is lower than the single-mesh in the majority of the examples; this process is controlled by the stiff behavior of the reactive term. The problem size of the multimesh scheme is much lower, and therefore, larger spatial discretizations can be simulated for a given available memory. The efficiency of the multimesh strategy increases with the number of species and the number of species that develop a plume. Finally, an example of a punctual emission considering realistic values of the initial concentrations and using the Community Multiscale Air Quality-CBO5 reaction model, which involves 62 components, is presented; the small-scale structure of the different nitrogen components near the emitter is capture
CitationMonforte, L.; Pérez-Foguet, A. A multimesh adaptive scheme for air quality modeling with the finite element method. "International journal for numerical methods in fluids", 2014, vol. 74, p. 387-405.