Shallow-water models with anisotropic porosity and merging for flood modelling on Cartesian grids

Bruwier, Martin; Archambeau, Pierre; Erpicum, Sébastien; Pirotton, Michel; Dewals, Benjamin

doi:10.1016/j.jhydrol.2017.09.051

Cited by 50 publications

(56 citation statements)

References 24 publications

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“…The IP model is known to underestimate the wave propagation speeds of transients in the presence of obstacles, a drawback that is eliminated to a large extent by the DIP model. A depth-independent porosity model derived from independent considerations [6] has also been shown to achieve improved wave propagation properties when made consistent with the DIP uxes. The DIP model also incorporates a transient momentum dissipation mechanism, active only for positive waves.…”

Section: Introductionmentioning

confidence: 99%

Flux closures and source term models for shallow water models with depth-dependent integral porosity

Guinot

Delenne

Rousseau

et al. 2018

Advances in Water Resources

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A two-dimensional shallow water model with depth-dependent porosity is presented. The purpose is the coarse grid simulation of shallow ows over complex topographies and geometries. Two ux closures are examined: the Integral Porosity (IP) and Dual Integral Porosity (DIP) closures. Energy losses are described using a subgrid scale model that accounts for bottom and wall friction, transient momentum dissipation and energy losses induced by obstacle submersion. A complete wave propagation property analysis is provided for the IP and DIP closures, yielding more accurate numerical stability constraints than published previously. Five computational examples are presented, including transients in compound and meandering channels, urban dambreak problems with building submersion and runo over variable microtopography. The ability of the model to deal with subgrid-scale features is conrmed. The DIP ux is shown to be superior to the IP closure. The transient dissipation term is essential in reproducing the eect of obstacles and microtopography. Distinguishing between the building wall-and building roof-induced friction is seen to be essential. The model is validated successfully against a scale model experimental dataset for the submersion of a coastal urban area by a tsunami wave.

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Section: Introductionmentioning

confidence: 99%

Flux closures and source term models for shallow water models with depth-dependent integral porosity

Guinot

Delenne

Rousseau

et al. 2018

Advances in Water Resources

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“…• isotropic and anisotropic porosity-based models (e.g., Bruwier et al (2017)), coupled 1D (in streets) and 2D (in crossroads) models (Ghostine et al, 2015), as well as improved computational techniques such as cloud computing (Glenis et al, 2013) or model implementation on graphical processing unit (Apel et al, 2016;Smith et al, 2015), have been developed to enable efficient coverage of large spatial areas;…”

Section: Introductionmentioning

confidence: 99%

Experimental modelling of urban flooding: A review

Mignot

Dewals

2019

Journal of Hydrology

163

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We review the 45 available studies of urban flooding based on laboratory experiments. We distinguish between the studies focusing on the flow in (i) a single street intersection, (ii) surface-sewer exchanges, (iii) an array of obstacles and (iv) quasi-realistic urban districts. We discuss the main flow processes which are covered in the various studies and detail which flow variables were recorded. This enables identifying flow processes for which comprehensive experimental datasets are available from those which require additional experimental research. We also highlight the typical ranges of scale factors used, which depend mainly on the extent of the studied area (from very local up to the district level). This review aims at helping computational modellers to pinpoint the most suitable dataset for validating their numerical approaches and laboratory modellers to identify gaps in current experimental knowledge of urban flooding.

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“…The shallow water equations with porosity are most commonly used for flood simulations in urban areas, e.g. [1][2][3][4][5][6][7][8][9][10][11]. Another type of shallow water equations with porosity are applied to rainfall-runoff simulations in natural catchments, [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

“…Obviously, a good candidate is the finite volume method. Attempts to reduce the mesh dependency of IP model results are made in [11,16], where the conveyance porosity of an edge is related to the smallest length parallel to the edge that is available to the flow.…”

Section: Introductionmentioning

confidence: 99%

Numerical study of building drag dissipation for- mulations in the integral porosity shallow water model

et al. 2018

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The integral porosity shallow water model is a type of porous shallow water model for urban flood modeling, that defines two types of porosity, namely a volumetric porosity inside the computational cell and a conveyance porosity at each edge. Porosity terms are determined directly from the underlying building geometry, hence buildings do not need to be discretized exactly. This enables simulations with significantly reduced CPU time on meshes with cell sizes larger than the building size. Here, the macroscopic model view leads to an additional source term at the unresolved building-fluid interface, yielding a building drag dissipation source term. In literature, several formulations for this term can be found. The integral porosity shallow water model is sensitive to the building drag dissipation, and using the drag parameters as a calibration parameter enhances the accuracy of model results. However, the ideal way to achieve this is still an open research question. In this contribution, we present a simple technique to estimate building drag dissipation that uses the conveyance porosity configuration to estimate the projected area inside the cell, which is then used in a drag force equation. The advantage of this approach is that it is computationally inexpensive, no additional parameters need to be stored, and only a single parameter has to be calibrated. The proposed approach is compared with drag dissipation formulations from existing literature in a laboratory experiment that features a dam-break against an isolated obstacle. The aim of the comparison is to evaluate present existing building drag dissipation models with regard to accuracy and computational cost.

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Shallow-water models with anisotropic porosity and merging for flood modelling on Cartesian grids

Cited by 50 publications

References 24 publications

Flux closures and source term models for shallow water models with depth-dependent integral porosity

Flux closures and source term models for shallow water models with depth-dependent integral porosity

Experimental modelling of urban flooding: A review

Numerical study of building drag dissipation for- mulations in the integral porosity shallow water model

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