Hydraulic modelling in civil and environmental engineering

Scientific conference (2013, May 08)

Effects of climate change on the river Meuse: Hydraulic 2D modeling from Amspin to Maaseik (and beyond)

Poster (2013, March 22)

Impact of climate change on inundation hazard along the river Meuse

in Transboundary Water Management in a Changing Climate (2013, March)

As a part of the effort to scientifically inform the development of the adaptation strategy for the Meuse basin, we detail hereafter the generation of integrated climate and hydrological scenarios for the ... [more ▼]

As a part of the effort to scientifically inform the development of the adaptation strategy for the Meuse basin, we detail hereafter the generation of integrated climate and hydrological scenarios for the whole basin. We also present the setup of a first coordinated hydraulic modelling from spring to mouth of the river Meuse. The latter has enabled to compute the range of change in inundation hazard under the “wet” transnational hydrological scenario for the time slices 2021-2050 and 2071-2100. A significantly higher impact of climate change has been found in the middle part of the Meuse basin, compared to the upper and the lower parts. These conclusions have been further confirmed by a refined analysis conducted for a 100 km-long stretch of the river Meuse crossing the Belgian-Dutch border. [less ▲]

Transboundary hydraulic modelling of extreme floods in the Meuse River

in The Wise Find Pleasure in Water (2013)

Detailed inundation modelling was conducted along a 100 km long transnational section of the Meuse River (in Belgium and The Netherlands), using very similar models for the whole computation (2D unsteady ... [more ▼]

Detailed inundation modelling was conducted along a 100 km long transnational section of the Meuse River (in Belgium and The Netherlands), using very similar models for the whole computation (2D unsteady models). As a result, damping of the flood waves could be quantified and the possible relevance of using a steady-state approach could be assessed. The new detailed 2D hydraulic simulations have demonstrated that only a very limited damping of the flood waves occurs along the simulated reaches. From the perspective of the variation in peak discharge, the study concludes that running the hydraulic model in steady mode makes perfectly sense. Nonetheless, the steady computations lead to extensive overestimations of the inundated extent and of the stored volume in the floodplains. The 2D unsteady model constitutes also a tool of primary interest, which is readily available to design and evaluate protection measures for flood-prone areas such as in the city of Liege. [less ▲]

Dike-break induced flows: a simplified model

in Environmental Fluid Mechanics (2013), 13(1), 89-100

A simplified model for the prediction of the steady-state outflowthrough a breach in an inland dike is presented. It consists in the application of the mass and momentum conservation principles to a ... [more ▼]

A simplified model for the prediction of the steady-state outflowthrough a breach in an inland dike is presented. It consists in the application of the mass and momentum conservation principles to a macroscopic control volume. A proper definition of the shape of the control volume enables to take the main characteristics of the flow into account and thus to compensate for the extreme simplification of the spatial representation of the model. At the breach, a relation derived from the shallow-water equations is used to determine the direction of the flow. Developments have been guided by numerical simulations and results have been compared to experimental data. Both the accuracy and the domain of validity of the simplified model are found satisfactory. [less ▲]

Experiment investigations of 2D stationary mixed flows and numerical conparison

in Proceedings of the 2nd IAHR Europe Congress (2012, June 27)

Experimental investigations have been carried out to observe the mechanisms of stationary mixed flows in a flume combined with a conduit. The tests have been performed for varied discharges, considering ... [more ▼]

Experimental investigations have been carried out to observe the mechanisms of stationary mixed flows in a flume combined with a conduit. The tests have been performed for varied discharges, considering two 4.2m long rectangular channels 0.985m wide and 0.50m deep, linked by a 2m long closed conduit with a 0.20m wide and 0.15m high rectangular cross-section, located at the channels bottom along the right bank. The experimental results have been compared with numerical modeling performed using an original 2D numerical model, dealing with mixed flows using a single set of equations. [less ▲]

Three‐phase Bi‐layer Model for Simulating Mixed Flows

in Journal of Hydraulic Research (2012), 50(3), 312-319

Mixed flows characterized by a simultaneous occurrence of free surface and pressurized flows are often encountered in hydraulic engineering. Numerous researches have been dedicated to unify the ... [more ▼]

Mixed flows characterized by a simultaneous occurrence of free surface and pressurized flows are often encountered in hydraulic engineering. Numerous researches have been dedicated to unify the mathematical description of both flows. Herein, shock-capturing models succeed in giving a unique set of equations. However, no method accounts for both air-entrapment and air-entrainment. This study proposes an original model to simulate air–water interactions in mixed flows. The new approach relies on the area-integration of a three-phase model over two layers. The applicability of this free surface model is extended to pressurized flows by a modified pressure term accounting for the dispersed air. The derived modelling system WOLF IMPack is then validated. The code successfully simulates open channel flows, mixed flows and water hammer in a unified framework, including air–water interactions, in structures like the drainage network. [less ▲]

Hydraulic modelling of Piano Key Weirs: a composite approach

in Proceedings of International workshop on Piano Key Weir for In-stream Storage and Dam Safety - PKWISD-2012 (2012, May)

During the last few years, several piano key weirs (PKWs) have been built in France and abroad. Thanks to the reduced footprint and high release capacities of this new type of weir, making it particularly ... [more ▼]

During the last few years, several piano key weirs (PKWs) have been built in France and abroad. Thanks to the reduced footprint and high release capacities of this new type of weir, making it particularly suited for concrete dams rehabilitation, lots of other projects in various countries are under construction or study. The prototype use of PKW requires knowledge about its structural behaviour, hydraulic capacities as well as integration into dams’ environment. This paper aims at presenting numerical and physical modelling works performed at the University of Liege to address the last two items. In particular, large scale physical modelling and parametric scale models have enabled to understand the hydraulic behaviour of the structure and to highlight its most influencing geometric parameters as well as their best variation interval depending on various criteria related to the weir design (discharge efficiency, cost…). A 1D numerical model has also been developed based on these experimental investigations. It enables to predict in a few minutes, with 10% accuracy, the discharge capacity of a given PKW geometry within its usual range of operation head. This model, available as a freeware from http://www.pk-weirs.ulg.ac.be, constitutes a key tool for the first design of such weirs. Finally, the scale model studies of major projects such as Raviège dam (France) for Electricité de France - EDF and Ouldjet Mellegue Project (Algeria) for Coyne et Bellier – Tractebel Engineering enable to confront theoretical predictions with experimental results and to address the problem of PKW integration on dam crests. [less ▲]

Relative impacts of climate and landuse changes on future flood damage along River Meuse in Wallonia

Poster (2012, April 27)

Climate change is expected to increase flood hazard across most of Europe, both in terms of peak discharge intensity and frequency. Consequently, managing flood risk will remain an issue of primary ... [more ▼]

Climate change is expected to increase flood hazard across most of Europe, both in terms of peak discharge intensity and frequency. Consequently, managing flood risk will remain an issue of primary importance for decades to come. Flood risk depends on territories’ flood hazard and vulnerability. Beside climate change, land use evolution is thus a key influencing factor on flood risk. The aim of this research is to quantify the relative influence of climate and land use changes on flood damage evolution during the 21st century. The study focuses on River Meuse in Wallonia for a 100-year flood. A scenario-based approach was used to model land use evolution. Nine urbanization scenarios for 2100 were developed: three of them assume a “current tend” land use evolution, characterized by urban sprawl, while six others assume a sustainable spatial planning, leading to an increase in density of residential areas as well as an increase in urban functions diversity. A study commissioned by the EU has estimated a 30 % increase in the 100-year discharge for River Meuse by the year 2100. Inundation modeling was conducted for the present day 100-year flood (HQ100) and for a discharge HQ100 + 30%, using the model Wolf 2D and a 5m grid resolution Digital Elevation Model (Ernst et al. 2009). Based on five different damage curves related to land use categories, the relative damage was deduced from the computed inundation maps. Finally, specific prices were associated to each land use category and allowed assessing absolute damages, which were subsequently aggregated to obtain a damage value for each of the 19 municipalities crossed by River Meuse. Results show that flood damage is estimated to increase by 540 to 630 % between 2009 and 2100, reaching 2.1 to 2.4 billion Euros in 2100. These increases mainly involve municipalities downstream of a point where the floodplain width becomes significantly larger. The city of Liège, which is protected against a 100-year flood in the present situation, would undergo about 450 million Euros damage for a 100-year flood in the 2100, i.e. in-between 21% and 25 % of the whole damage increase. The influence of climate is three to eight times higher than the effect of land use change according to the land use evolution scenarios considered. Nevertheless, these two factors have a comparable influence on seven municipalities. Consequently, although a careful spatial planning would not considerably reduce the overall flood damage at the level of theWalloon part of the Meuse Valley, more sustainable spatial planning could efficiently reduce future flood damage at the level of several most critical municipalities. Reference Ernst, J, Dewals, B, Detrembleur, S, Archambeau, P, Erpicum, S, & Pirotton, M. (2010). Micro-scale flood risk analysis based on detailed 2D hydraulic modelling and high resolution geographic data. Natural Hazards, 55(2), 181-209. [less ▲]

Barrage de Sarrans - Vidange de fond - Modèle réduit hydraulique

Report (2012)