Handling very different space- and time-scales in numerical modeling of flows with sediment transport

The numerical models for flow and sediment transport must be able to handle properly the wide range of space- and time-scales relevant for the processes to be modelled. For this purpose different levels of numerical coupling between the flow solver and the sediment transport model must be considered. Besides a short review of the mathematical background, the present paper describes the modelling system WOLF, developed at the University of Liege and enabling to handle the vast majority of time scales characterizing practical applications of flows with sediment transport, by means of specific numerical techniques. The applicability of the modeling system is demonstrated based on several examples of simulations related to the design and the operation of a large hydroelectric project in India.Les mod?les num?riques hydros?dimentaires doivent ?tre aptes ? prendre en compte la tr?s grande h?t?rog?n?it? des ?chelles spatiales et surtout temporelles affectant les divers ph?nom?nes ? simuler. Pour ce faire, diff?rents niveaux de couplage entre sous-mod?les doivent ?tre pr?vus (calcul hydrodynamique stationnaire, quasi stationnaire ou instationnaire complet). Outre une discussion du formalisme math?matique sous-jacent, la pr?sente communication d?crit le syst?me de mod?lisation WOLF, d?velopp? ? l'Universit? de Li?ge et permettant de couvrir la majorit? des ?chelles de temps pertinentes au moyen d'approches num?riques sp?cifiquement adapt?es. L'applicabilit? du syst?me de mod?lisation est illustr?e sur base de plusieurs exemples de simulations relatives ? la conception et aux modes de gestion d'un grand ouvrage hydro?lectrique en Inde.