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| Titel |
Assessment of numerical schemes for solving the advection–diffusion equation on unstructured grids: case study of the Guaíba River, Brazil |
| VerfasserIn |
F. F. Pereira, C. R. Jr. Fragoso, C. B. Uvo, W. Collischonn, D. M. L. Motta Marques |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 20, no. 6 ; Nr. 20, no. 6 (2013-12-17), S.1113-1125 |
| Datensatznummer |
250086083
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| Publikation (Nr.) |
 copernicus.org/npg-20-1113-2013.pdf |
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| Zusammenfassung |
| In this work, a first-order upwind and a high-order flux-limiter schemes for
solving the advection–diffusion equation on unstructured grids were
evaluated. The numerical schemes were implemented as a module of an
unstructured two-dimensional depth-averaged circulation model for shallow
lakes (IPH-UnTRIM2D), and they were applied to the Guaíba River in
Brazil. Their performances were evaluated by comparing mass conservation
balance errors for two scenarios of a passive tracer released into the
Guaíba River. The circulation model showed good agreement with observed
data collected at four water level stations along the Guaíba River, where
correlation coefficients achieved values up to 0.93. In addition, volume
conservation errors were lower than 1% of the total volume of the
Guaíba River. For all scenarios, the higher order flux-limiter scheme has
been shown to be less diffusive than a first-order upwind scheme. Accumulated
conservation mass balance errors calculated for the flux limiter reached
8%, whereas for a first-order upwind scheme, they were close to 18%
over a 15-day period. Although both schemes have presented mass conservation
errors, these errors are assumed negligible compared with kinetic processes
such as erosion, sedimentation or decay rates. |
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