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Flood Risk in Liege Area: A Transnational Perspective Dewals, Benjamin ; Archambeau, Pierre ; Erpicum, Sébastien et al in Hydrolink (2015), (3), Liege is located at the heart of the Meuse basin, which covers parts of France, Belgium, Germany and the Netherlands. Considering explicitly this transnational context when conducting flood risk analysis ... [more ▼] Liege is located at the heart of the Meuse basin, which covers parts of France, Belgium, Germany and the Netherlands. Considering explicitly this transnational context when conducting flood risk analysis in the area of Liege sheds light on specific features and management opportunities which might otherwise be overlooked. Within a basin-wide collaborative approach, future flood risk was estimated along the course of the Meuse and adaptation measures were evaluated, particularly for the protection of the city of Liege. [less ▲] Detailed reference viewed: 12 (0 ULg)Closure to “Parapet Wall Effect on Piano Key Weir Efficiency” Erpicum, Sébastien ; ; Pirotton, Michel et al in Journal of Irrigation & Drainage Engineering (2015), 141(1), 07014033 Detailed reference viewed: 32 (3 ULg)Pressure and velocity on an ogee spillway crest operating at high head ratio: experimental measurements and instrumentation Peltier, Yann ; Dewals, Benjamin ; Archambeau, Pierre et al in Carvalho, Rita; Pagliara, Stefano (Eds.) 2nd International workshop on hydraulic structures: data validation (2015) This paper aims at validating pressure and velocity measurements conducted in two physical scale models of an ogee spillway crest operating at heads largely greater than the design head. The design head ... [more ▼] This paper aims at validating pressure and velocity measurements conducted in two physical scale models of an ogee spillway crest operating at heads largely greater than the design head. The design head of the second model is 50% smaller than the one of the first model. No piles effect or air entrance is considered in the study. The velocity field is measured by Large Scale Particle Image Velocimetry. The relative pressure along the spillway crest is measured using pressure sensors. Comparisons of measured velocities between both spillways indicate low scale effects, the scaled-profiles collapsing in most parts of the flow. By contrast, measurements of relative pressure along the spillway crest differ for large heads. A theoretical velocity profile based on potential flow theory and expressed in a curvilinear reference frame is then fitted to the velocity measurements, considered as reference, for extrapolating the velocity at the spillway crest. Comparing the extrapolated velocity at the spillway crest and the velocity expressed from the relative pressure finally emphasizes that bottom pressure amplitudes are overestimated for the large spillway, while an averaging effect might operate for the pressure measurements on the small spillway. [less ▲] Detailed reference viewed: 49 (0 ULg)A modular approach dedicated to dam-break and dam-breaching modelling Stilmant, Frédéric ; Dewals, Benjamin ; Erpicum, Sébastien et al in Advances in Hydroinformatics (2015) The paper presents an integrated tool for dam-break hazard modelling. It is based on a two-dimensional, depth-averaged hydraulic model that uses a conservative and shock-capturing finite volume scheme on ... [more ▼] The paper presents an integrated tool for dam-break hazard modelling. It is based on a two-dimensional, depth-averaged hydraulic model that uses a conservative and shock-capturing finite volume scheme on a Cartesian grid. The hydraulic model is designed so that different zones within the computation domain can be modelled with different spatial resolutions and/or different model enhancements (e.g. pressurised flows, sediment transport, etc.). The two-dimensional model can be coupled with lumped models that compute the water stage in reservoirs and the outflow discharge through hydraulic structures, in case of normal operating, failure of a valve or breaching processes. These features make hydraulic modelling versatile and computationally efficient. They enable the definition of different failure scenarios, which is of prominent importance given the uncertainty of such a phenomenon. If several hydraulic structures are involved, the procedure takes the behaviour of each structure into account. The sensitivity of the results with respect to the interactions between the flow and the terrain (roughness coefficient, collapse of buildings, breaching process) can be analysed. The results of the hydraulic model are handled thanks to a graphical user interface that provides one-, two- and three-dimensional views and animations of the unsteady flow-field and enables the understanding and verification of the results. Danger maps are generated based on the results of one or more ‘worst-case’ scenarios. In case of a complete risk analysis, the danger maps are combined with data on the exposure and vulnerability of elements at risk for the computation of the corresponding damage. [less ▲] Detailed reference viewed: 29 (6 ULg)Can meandering flows in shallow rectangular reservoir be modelled with the 2D shallow water equations? Peltier, Yann ; Erpicum, Sébastien ; Archambeau, Pierre et al in Journal of Hydraulic Engineering (2015) In this article, the ability of the 2D shallow water equations to model meandering flows in shallow rectangular reservoirs is discussed. Four meandering flows, of various shallowness, were modelled using ... [more ▼] In this article, the ability of the 2D shallow water equations to model meandering flows in shallow rectangular reservoirs is discussed. Four meandering flows, of various shallowness, were modelled using the academic flow model WOLF 2D, which includes a depth-averaged k- model accounting for the horizontal and vertical turbulent length-scales. The bottom friction was modelled with the Colebrook-White formula and different roughness heights were considered. A Proper Orthogonal Decomposition (POD) was applied to the simulation results to extract the behaviour of the main structures responsible for the meandering flow. The same POD analysis was also performed for the reference experimental flow fields, obtained by Large-Scale Particle Image Velocimetry. The first two POD modes obtained from the numerical simulations assuming a smooth bottom are in good agreement with the experimental modes in terms of energy, as well as temporal and spatial variations, whatever the shallowness. In contrast, the remaining simulated modes are not well rendered. The effect of an increased roughness height in the simulations is finally discussed. It leads to an improved reproduction of the first two modes and of the following modes, except when significant viscous effects govern in the flow. [less ▲] Detailed reference viewed: 94 (42 ULg)Se barricader : une solution insuffisante face à l'eau ; Archambeau, Pierre ; Erpicum, Sébastien et al Article for general public (2014) Detailed reference viewed: 23 (4 ULg)Integrated catchment analysis in the Meuse basin for assessing water resources and future flood risk Dewals, Benjamin ; Archambeau, Pierre ; Bruwier, Martin et al Conference (2014, November 12) Detailed reference viewed: 21 (5 ULg)Potential damping of extreme floods in the river Meuse (Phase I): 1st progress report Bruwier, Martin ; Archambeau, Pierre ; Erpicum, Sébastien et al Report (2014) Detailed reference viewed: 22 (7 ULg)Prediction of mean and turbulent kinetic energy in rectangular shallow reservoirs ; Erpicum, Sébastien ; Archambeau, Pierre et al in Engineering Applications of Computational Fluid Mechanics (2014), 8(4), Shallow rectangular reservoirs are common structures in urban hydraulics and river engineering. Despite their simple geometry, complex symmetric and asymmetric flow fields develop in such reservoirs ... [more ▼] Shallow rectangular reservoirs are common structures in urban hydraulics and river engineering. Despite their simple geometry, complex symmetric and asymmetric flow fields develop in such reservoirs, depending on their expansion ratio and length-to-width ratio. The original contribution of this study is the analysis of the kinetic energy content of the mean flow, based on UVP velocity measurements carried throughout the reservoir in eleven different geometric configurations. A new relationship is derived between the specific mean kinetic energy and the reservoir shape factor. For most considered geometric configurations, leading to four different flow patterns, the experimentally observed flow fields and mean kinetic energy contents are successfully reproduced by an operational numerical model based on the depth-averaged flow equations and a two-length-scale k-e turbulence closure. The analysis also highlights the better performance of this depth-averaged k-e model compared to an algebraic turbulence model. Finally, the turbulent kinetic energy in the reservoir is derived from the experimental measurements and the corresponding numerical predictions based on the k-e model agree satisfactorily in the main jet but not in the recirculation zones. [less ▲] Detailed reference viewed: 56 (7 ULg)Hydrological and hydraulic modelling in environmental and civil engineering Dewals, Benjamin ; Erpicum, Sébastien ; Archambeau, Pierre et al Conference (2014, October 06) Detailed reference viewed: 32 (9 ULg)Landuse change and future flood risk: the influence of micro-scale spatial patterns (FloodLand) - 2nd progress report Dewals, Benjamin ; Bruwier, Martin ; El Saeid Mustafa, Ahmed Mohamed et al Report (2014) The goal of the project FloodLand is to investigate the complex interactions between landuse change and future flood risk. Landuse change is assumed to be mainly driven by population growth and socio ... [more ▼] The goal of the project FloodLand is to investigate the complex interactions between landuse change and future flood risk. Landuse change is assumed to be mainly driven by population growth and socio-economic factors. It affects future flood risk by altering catchment hydrology as well as vulnerability in the floodplains; but the feedback effect of (the perception of) changes in flood hazard on landuse evolution is also considered. The research is based on a chain of modelling tools, which represent parts of the natural and human systems, including: landuse change modelling, transportation modelling as an onset for the estimation of indirect flood damage, continuous hydrological modelling (forced by precipitation and temperature data disturbed according to climate change scenarios), as well as efficient hydraulic modelling of inundation flow in the floodplains. Besides reproducing a broad spectrum of processes, the modelling approach spans over multiple scales, from the regional or catchment level down to the floodplain and building levels. This distinctive feature is reflected both within the individual models and through their combination involving fine-scale detailed analyses (or data) embedded within coarser models at a broader level. [less ▲] Detailed reference viewed: 88 (40 ULg)Velocity and turbulence measurements for assessing the stability of riverbeds: a comparison between UVP and ADVP Duma, Diana ; Erpicum, Sébastien ; Archambeau, Pierre et al in 11th International Conference on Hydroscience & Engineering - "Hydro-Engineering for Environmental Challenges" (2014, October) Maintaining the overall stability of active riverbeds requires a deep understanding of the complex interactions between turbulent flow forces and forces stabilizing the riverbed. Standard approaches do ... [more ▼] Maintaining the overall stability of active riverbeds requires a deep understanding of the complex interactions between turbulent flow forces and forces stabilizing the riverbed. Standard approaches do not properly take into account the turbulence fluctuations in non-uniform flows, while these are of primary importance in the mechanisms determining the stability of stones. In a new approach, the flow forces are quantified by means of parameters combining explicitly the velocity and turbulence distributions over a certain water depth above the riverbed. In this paper, as an onset for using these newly developed bed stability parameters, we report on new experimental measurements of velocity and turbulent kinetic energy based on acoustic methods, whereas all previous uses at the new bed stability parameters relied on Laser PIV Techniques. For quasi-uniform and non-uniform flow conditions, velocity measurements were conducted with two complementary devices: an ultrasonic velocimeter probe (UVP) and an acoustic Doppler velocimeter profiler (ADVP). The results are compared and discussed in detail. A general consistency between the two types of measurements is obtained, while some discrepancies are highlighted close to the bed and tentative explanations are given. [less ▲] Detailed reference viewed: 59 (12 ULg)Towards enhanced estimates of future water demand in the Meuse basin Dewals, Benjamin ; Archambeau, Pierre ; Erpicum, Sébastien et al Conference (2014, September 18) Detailed reference viewed: 8 (2 ULg)Flow and turbulence characterization as an onset for assessing the stability of gravel beds Duma, Diana ; Erpicum, Sébastien ; Archambeau, Pierre et al in 7th International Conference on Fluvial Hydraulics (2014, September) The flow characteristics, such as velocity profiles and turbulence intensities, are of high practical relevance in the assessment of riverbed stability. So far, the Shields diagram remains the most widely ... [more ▼] The flow characteristics, such as velocity profiles and turbulence intensities, are of high practical relevance in the assessment of riverbed stability. So far, the Shields diagram remains the most widely accepted approach for defining the initiation of sediment motion. However, it faces a number of shortcomings. In principle, it is only valid for uniform flow conditions and, under non-uniform flow conditions, it fails to account properly for the influence of turbulence in sediment entrainment. In this paper, we focus on a more detailed description of quasi-uniform and non-uniform flow characteristics in the vicinity of the critical flow conditions for inception of motion of gravel beds. Laboratory experiments were designed, involving two configurations. First, the entire bottom of the flume was paved with stones of uniform diameter (8 or 15 mm), leading to quasi-uniform flow conditions. Second, the flume bottom was smooth upstream of the zone of measurement while the downstream part was covered with gravels, leading to a sudden smooth-to-rough transition. The flow velocity was obtained by acoustic measurements and the turbulence intensity was calculated for both configurations. By fitting the velocity profile to a modified logarithmic law, the shear velocity was estimated. Standard approaches for predicting the threshold of motion, initially developed for uniform flows, were compared to other methods, based on depth-averaged turbulence kinetic energy, recently proposed in literature for non-uniform flow conditions. [less ▲] Detailed reference viewed: 65 (6 ULg)Towards enhanced estimates of future water demand in the Meuse basin: literature review ; Bruwier, Martin ; Archambeau, Pierre et al Report (2014) With respect to water management in the Meuse basin, the hydrological consequences of climate change have been taken into account in several studies so far; but this is not the case of many other ... [more ▼] With respect to water management in the Meuse basin, the hydrological consequences of climate change have been taken into account in several studies so far; but this is not the case of many other environmental and socio-economic changes, including trends in future water demand. The objective of this report is to serve as an onset for the development of a first approach to estimate at a relatively large-scale future water demand in the Meuse basin. Based on a review of recent literature, this report discusses the key drivers which influence water demand, with the aim of identifying the most suitable methods to implement in a subsequence more detailed analysis, as well as to highlight the data needs. [less ▲] Detailed reference viewed: 39 (14 ULg)La Meuse au fil des crues ; Dewals, Benjamin ; Archambeau, Pierre et al Article for general public (2014) Detailed reference viewed: 24 (5 ULg)Comparison between Experimental and SPH Models over a Sharp-crested Weir Lodomez, Maurine ; Erpicum, Sébastien ; Dewals, Benjamin et al Scientific conference (2014, August 28) In this paper the numerical simulations of a free surface flow over a sharp-crested weir are presented and compared to experimental results. The numerical model implemented consists of the meshless ... [more ▼] In this paper the numerical simulations of a free surface flow over a sharp-crested weir are presented and compared to experimental results. The numerical model implemented consists of the meshless Smoothed Particle Hydrodynamics (SPH) method which uses Navier-Stokes equations and the Tait equation of state for water. This numerical method has been developed in the framework of a master thesis and aimed to define the characteristics of the free jet. The validation of the results was performed through the analysis of the pressure field and the comparison of the numerical free surface profiles with experimental measurements conducted in the Hydraulic Laboratory of the University of Liège (ULg). A good qualitative agreement has been obtained. [less ▲] Detailed reference viewed: 38 (13 ULg)How to simulate quickly and efficiently a flow over a spillway ? Goffin, Louis ; Erpicum, Sébastien ; Dewals, Benjamin et al Conference (2014, August) Flows over hydraulic structures, such as weirs or spillways, can be modelled using different techniques. New models such as SPH or PFEM are becoming more and more popular. These models are particle and/or ... [more ▼] Flows over hydraulic structures, such as weirs or spillways, can be modelled using different techniques. New models such as SPH or PFEM are becoming more and more popular. These models are particle and/or meshless and consequently require a lot of computational power. Other methods such as VOF also require a lot of computational time. In the frame of 2-D vertical flows, other techniques use much less computation time. For irrotationnal flows, solving the Laplace equation can be done very efficiently. The difficulty of this method lies in the definition of boundary conditions. The free-surface, which is naturally determined when using Lagrangian methods, needs a heavy iterative solving due to its non-linear nature when expressed in the frame of the Laplace equation. This paper will present an original technique that allows a quicker and easier determination of the free-surface. An irregular mesh for boundaries is used and discussed. The method is validated with analytical solutions and experimental measurements. [less ▲] Detailed reference viewed: 63 (23 ULg)Etudes théorique et sur modèles numériques et physiques du déversoir à dépression - 3ième rapport intermédiaire - Thème 1: Etudes du coefficient de débit et des pressions sur le coursier des Creager pour des charges amont largement supérieures à la charge de dimensionnement Peltier, Yann ; Erpicum, Sébastien ; Pirotton, Michel et al Report (2014) Detailed reference viewed: 21 (2 ULg)Geometric parameters influence on Piano Key Weir hydraulic performances Erpicum, Sébastien ; Archambeau, Pierre ; Pirotton, Michel et al in Chanson, Hubert; Toombes, Luke (Eds.) Hydraulic Structures and Society – Engineering Challenges (2014, June) The Piano Key Weir is a recent evolution of the traditional labyrinth weir. Thanks to a reduced foot print, this nonlinear weir can be placed on the top of gravity dams. The Piano Key Weir geometry ... [more ▼] The Piano Key Weir is a recent evolution of the traditional labyrinth weir. Thanks to a reduced foot print, this nonlinear weir can be placed on the top of gravity dams. The Piano Key Weir geometry involves a large number of geometric parameters. Several experimental studies have been carried out to investigate the main geometric parameters influencing the weir hydraulic efficiency and to define their optimal value. In this paper, the experimental data gathered at the University of Liege are re-examined to show how the weir height, the keys widths and the overhangs positions influence, for a given crest length magnification ratio, the weir discharge capacity. The theoretical rating curve of a standard linear weir is considered for comparison. The analysis highlights that the keys widths and overhangs lengths ratios influence significantly the Piano Key Weir efficiency, but less than the weir height. Considering the above mentioned results, a cost efficient design proposed in the literature is also proved to be close to the hydraulic optimum. [less ▲] Detailed reference viewed: 40 (2 ULg) |
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