Free surface flows over mobile bed: mathematical analysis and numerical modeling of coupled and decoupled approaches

G. GaregnaniG. Rosatti, L. Bonaventura

in COMMUNICATIONS IN APPLIED AND INDUSTRIAL MATHEMATICS, v. 2, n. 1 (2011). - DOI: 10.1685/journal.caim.371 



In the case of high sediment concentration regimes in rivers, morphodynamics is usu-
ally described by means of coupled models derived from a quasi two-phase (solid and
liquid) approach. On the contrary, in the case of low concentration regimes, simpli ed
equations (decoupled models) are typically employed. In this work, rstly, a decoupled
system of equations is consistently derived from the coupled system and its limit of valid-
ity is clearly provided. Secondly, we propose an ecient semi-implicit, semi-Lagrangian
technique that can be applied to both the approaches. Finally, results for idealized and
realistic test cases are presented in order to highlight the capabilities of the proposed
numerical scheme as well as to show the possible di erent behavior of the two models.


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