References of "Rulot, François"
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See detailPhysical and numerical modelling in low-head structures design
Dewals, Benjamin ULg; Archambeau, Pierre ULg; Rulot, François ULg et al

in Bung, Daniel; Pagliara, Stefano (Eds.) Proceedings of the International Workshop on Hydraulic Design of Low-Head Structures (2013, February)

Physical and numerical modelling may be combined within so-called composite or hybrid modelling. This enables to optimally take benefit of the respective strengths of each modelling approach, while ... [more ▼]

Physical and numerical modelling may be combined within so-called composite or hybrid modelling. This enables to optimally take benefit of the respective strengths of each modelling approach, while compensating for their specific drawbacks. Different types of composite modelling may be identified, such as embedding a detailed physical model within a broader scale numerical model, interconnecting different physical and numerical models focusing each on specific processes, or validating a numerical model from experimental data before exploiting the numerical model to generate more results than availa-ble from the experimental facility. Besides, specifically in more basic research, composite modelling may also be used to improve in-depth understanding of the relative importance of different processes which act simultaneously in the experimental test and may be artificially separated in numerical simulations. [less ▲]

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See detailLong-term sediment management for sustainable hydropower
Dewals, Benjamin ULg; Rulot, François ULg; Erpicum, Sébastien ULg et al

in Sayigh, A (Ed.) Comprehensive Renewable Energy. Vol. 6 (2012)

Since the second half of the 20th century and for decades to come, sedimentation in reservoirs is challenging our ability to maintain the storage capacity needed for water supply, flood mitigation and ... [more ▼]

Since the second half of the 20th century and for decades to come, sedimentation in reservoirs is challenging our ability to maintain the storage capacity needed for water supply, flood mitigation and hydroelectricity production. This complex issue needs to be accounted for from the early stages of the design of dams and reservoirs, until the definition of operation rules oriented towards sustainable management of water and sediments. With reference to the widely-used Driver, Pressure, State, Impact, Response (DPSIR) analytical framework (European Commission 2003), the present chapter reviews key figures and trends in worldwide reservoirs sedimentation, as well as analyzes contemporary sediment management strategies. Besides setting some fundamentals of reservoir sedimentation and summarizing up-to-date background information on rate and distribution of loss of storage in the world, we identify some key driving forces of soil erosion, such as land use, urban development, agriculture and deforestation. Main mechanisms of watershed erosion and sediment yield to reservoirs are also discussed, with a focus on their spatial and temporal variation. Means for quantifying the magnitude of this pressure on reservoirs sustainability are presented, including reservoir surveys, fluvial measurements and combined approaches with numerical modelling. After a review of sedimentation impacts, both locally and downstream as well as upstream of the reservoir, we describe current experience and future opportunities of response to reservoir sedimentation. Possible measures are classified into three broad categories: sediment yield reduction, sediment routing (bypass and pass-through) and sediment removal (dredging and flushing). Pro and contras are presented for the different modes of reservoir operation, as well as their expected efficiency and some specific constraints. Predicting the sedimentation pattern as well as grain sorting processes is a prerequisite for developing optimal sediment evacuation strategies, involving for instance flushing operations. Sound modelling of sediment transport and deposition in reservoirs is highlighted as highly beneficial to support sediment management in the perspective of achieving reservoir sustainability. The chapter also illustrates how spatially distributed numerical modelling may succeed in enhancing decision-making for selecting optimal sediment management measures. [less ▲]

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See detailMultidimensional flow modelling to guide hydromorphological restoration of an Alpine river
Rulot, François ULg; Detrembleur, Sylvain; Archambeau, Pierre ULg et al

in Proceedings of the 9th International Symposium on Ecohydraulics 2012 (2012)

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See detailDealing with sediment transport over partly non-erodible bottoms
Rulot, François ULg; Dewals, Benjamin ULg; Archambeau, Pierre ULg et al

in Tullis, Blake; Chanson, Hubert (Eds.) Proc. 4th International Junior Researcher and Engineer Workshop on Hydraulic Strucutres, IJREWHS’12 (2012)

In depth-averaged flow and morphodynamic models using a finite volume discretization based on explicit time integration, a specific difficulty can arise during a computation: the computed sediment level ... [more ▼]

In depth-averaged flow and morphodynamic models using a finite volume discretization based on explicit time integration, a specific difficulty can arise during a computation: the computed sediment level can become lower than the level of a non-erodible bottom. The original developments presented in this paper enable to correct the non-physical sediment levels. The method, based on iterative limitation of the outward fluxes, is perfectly mass conservative and remains computationally efficient. The resulting model has been validated with several 1D benchmarks leading to configurations with sediment transport over non-erodible bottom. Two interesting experimental benchmarks are highlighted in this paper to show the efficiency of numerical simulations. In these benchmarks, the computation time has been verified not to increase by more than 15% when using the new method. [less ▲]

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See detailModelling sediment transport over partially non-erodible bottoms
Rulot, François ULg; Dewals, Benjamin ULg; Erpicum, Sébastien ULg et al

in International Journal for Numerical Methods in Fluids (2012), 70(2), 186-199

In depth- and cross section-averaged morphodynamic models, based on explicit time integration, it may happen that the computed bed level becomes lower than the top level of a non-erodible layer (e.g ... [more ▼]

In depth- and cross section-averaged morphodynamic models, based on explicit time integration, it may happen that the computed bed level becomes lower than the top level of a non-erodible layer (e.g. concrete, bedrock or armoured layer). This is a standard pitfall which has been addressed in different ways. In this paper, we present an original approach for avoiding computation of non-physical bed levels, using an iterative procedure to correct the outward sediment fluxes. The procedure is shown to be computationally efficient while it achieves a high accuracy in terms of mass conservation. We compare our original approach with the existing Struiksma’s method and with a reformulation of the problem in terms of mathematical optimization of a linear or non-linear objective function under linear constraints. The new procedure has been incorporated into an existing finite volume morphodynamic model. It has been validated with several 1D benchmarks leading to configurations with sediment transport over non-erodible bottom. The computation time has been verified not to increase by more than 15% compared to runs without non-erodible bottom. [less ▲]

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See detailConsidering non-alluvial layers in morphodynamic modelling
Rulot, François ULg; Erpicum, Sébastien ULg; Dewals, Benjamin ULg et al

Conference (2011, November)

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See detailHydromorphological restoration of Alpine rivers
Rulot, François ULg; Dewals, Benjamin ULg; Erpicum, Sébastien ULg et al

Conference (2011, November)

More and more efforts are undertaken to restore rivers in a state close to their natural conditions in order to meet the Water Framework Directive requirement. This directive commits EU member states to ... [more ▼]

More and more efforts are undertaken to restore rivers in a state close to their natural conditions in order to meet the Water Framework Directive requirement. This directive commits EU member states to achieve a good ecological status of all their water bodies. It became thus very important to develop river restoration such as fish passages, bank renaturation, natural bars or meanders. Another important component of river restoration schemes is the decommissioning of man-made structures. These interventions can have significant impact on the river hydrology, hydraulics and morphology, such as bed degradation or aggradation, bank failures. Predicting these impacts of restoration schemes on the river, especially for large scale projects, should rely on detailed numerical studies. To achieve this goal, we develop a methodology to analyse different scenarios of river restoration based on several criteria related to flow, sediment transport and environment. This method is applied to the case of a French alpine river in which five hydropower plants will be replaced by a unique underground hydropower plant on the same section of river. [less ▲]

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See detailA unified approach for sediment routing over partially non-erodible bottoms and wetting-drying areas
Rulot, François ULg; Dewals, Benjamin ULg; Archambeau, Pierre ULg et al

in Proceedings of the 34th IAHR World Congress (2011)

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See detailAdvanced topics in sediment transport modelling: non-alluvial beds and hyperconcentrated flows
Dewals, Benjamin ULg; Rulot, François ULg; Erpicum, Sébastien ULg et al

in Ginsberg, Silvia Susana (Ed.) Sediment transport (2011)

In this chapter, we first present an original two-phase flow model for the water-sediment mixture, acting as a unified basis for all our subsequent developments. Next, we focus on two topics in which we ... [more ▼]

In this chapter, we first present an original two-phase flow model for the water-sediment mixture, acting as a unified basis for all our subsequent developments. Next, we focus on two topics in which we have made original contributions, namely sediment routing on alluvial and non-alluvial beds and modelling of transient hyperconcentrated flows. In both cases, we use our original two-phase flow modelling framework to derive specific governing equations, for which we discuss their mathematical properties, detail appropriate finite volume numerical scheme and demonstrate their validity through a number of test cases. [less ▲]

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See detailProceedings of the International Symposium on Unsteady Sediment Transport - GESINUS 2010
Dewals, Benjamin ULg; Erpicum, Sébastien ULg; Rulot, François ULg et al

Book published by University of Liege (2010)

Complexity in sediment transport and morphological modelling stems specifically from the variety of relevant physical processes as well as from their multi-scale nature, both in space (from grain- to ... [more ▼]

Complexity in sediment transport and morphological modelling stems specifically from the variety of relevant physical processes as well as from their multi-scale nature, both in space (from grain- to catchment scale) and in time (from quasi-instantaneous bank failures to silting of reservoirs within decades). To address this, the HACH group has developed a unique modelling system, which offers high flexibility in coupling flow and sediment transport sub-models to cover the broad spectrum of relevant time scales. In this framework, the HACH has convened on 29 and 30 July 2010 an international symposium, during which recent advances in morphological modelling have been presented, as well as progresses in grain scale experiments and field measurements. The symposium was supported by the University of Liege and the Fund for Scientific Research FNRS. Contributions from many European countries were presented and discussed, including Austria, Belgium, France, Italy, Netherlands, United Kingdom and Switzerland. [less ▲]

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