Record Display for the EPA National Library Catalog


Main Title Evaluation of Numerical Schemes for Solving a Conservation of Species Equation with Chemical Terms.
Author Eskridge, Robert E. ; Demerjian., Kenneth L. ;
CORP Author Environmental Sciences Research Lab., Research Triangle Park, N.C.
Year Published 1977
Report Number EPA/600/J-77/119;
Stock Number PB-281 007
Additional Subjects Atmospheric models ; Reaction kinetics ; Air pollution ; Partial differential equations ; Numerical analysis ; Nonlinear differential equations ; Reprints ; Air quality
Library Call Number Additional Info Location Last
NTIS  PB-281 007 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 8p
Numerical methods are investigated for solving a system of continuity equations that contain linear and nonlinear chemistry as source and sink terms. It is shown that implicit, finite-difference approximations, when applied to the chemical kinetic terms, yield accurate results when the equations are linear, but give poor results when the equations are nonlinear. In fact, when the equations are nonlinear, the implicit finite-difference scheme will be unstable if delta t is large. It is shown that for urban and larger scale air quality simulation models, the advection and chemical terms are more accurate than implicit treatments of the chemistry.