Hydrodynamics of long-duration urban floods: experiments and numerical modelling
Flood risk in urbanized areas raises increasing concerns as a result of demographic and climate changes. Hydraulic modelling is a key component of urban flood risk analysis; yet, detailed validation data are still lacking for comprehensively validating hydraulic modelling of inundation flow in urban...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-06-01
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| Series: | Natural Hazards and Earth System Sciences |
| Online Access: | http://www.nat-hazards-earth-syst-sci.net/16/1413/2016/nhess-16-1413-2016.pdf |
| Summary: | Flood risk in urbanized areas raises increasing concerns
as a result of demographic and climate changes. Hydraulic modelling is a key
component of urban flood risk analysis; yet, detailed validation data are
still lacking for comprehensively validating hydraulic modelling of
inundation flow in urbanized floodplains. In this study, we present an
experimental model of inundation flow in a typical European urban district
and we compare the experimental observations with predictions by a 2-D
shallow-water numerical model. The experimental set-up is 5 m × 5 m
and involves seven streets in each direction, leading to 49
intersections. For a wide range of inflow discharges, the partition of the
measured outflow discharges at the different street outlets was found to
remain virtually constant. The observations also suggest that the street
widths have a significant influence on the discharge partition between
the different streets' outlets. The profiles of water depths along the
streets are mainly influenced by the complex flow processes at the
intersections, while bottom roughness plays a small part. The numerical
model reproduces most of the observed flow features satisfactorily. Using a
turbulence model was shown to modify the length of the recirculations in the
streets, but not to alter significantly the discharge partition. The main
limitation of the numerical model results from the Cartesian grid used,
which can be overcome by using a porosity-based formulation of the
shallow-water equations. The upscaling of the experimental observations to
the field is also discussed. |
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| ISSN: | 1561-8633 1684-9981 |