B. Noël, Soares S., Y. Zech Université catholique de Louvain
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WP3 : Flood Propagation WP3 : Flood Propagation Computation On The ‘Isolated Computation On The ‘Isolated Building Test Case’ And The Building Test Case’ And The ‘ ‘ Model City Flooding Model City Flooding Experiment Experiment ’ ’ B. Noël, Soares S., Y. Zech Université catholique de Louvain
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WP3 : Flood Propagation Computation On The ‘Isolated Building Test Case’ And The ‘ Model City Flooding Experiment ’. B. Noël, Soares S., Y. Zech Université catholique de Louvain. Overview. Numerical Model The ‘Isolated Building Benchmark’ Numerical modelling Numerical results - PowerPoint PPT Presentation
Transcript of B. Noël, Soares S., Y. Zech Université catholique de Louvain
WP3 : Flood PropagationWP3 : Flood PropagationComputation On The ‘Isolated Computation On The ‘Isolated
Building Test Case’ And The ‘Building Test Case’ And The ‘Model Model City Flooding Experiment City Flooding Experiment ’’
B. Noël, Soares S., Y. ZechUniversité catholique de Louvain
IMPACT - 3rd Workshop Novembre 2003
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OverviewOverview
• Numerical Model• The ‘Isolated Building Benchmark’
– Numerical modelling– Numerical results– Sensitivity analysis
• The ‘Model City Benchmark’– Numerical modelling– Numerical results– Sensitivity analysis
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OverviewOverview
• Numerical Model• The ‘Isolated Building Benchmark’
– Numerical modelling– Numerical results– Sensitivity analysis
• The ‘Model City Benchmark’– Numerical modelling– Numerical results– Sensitivity analysis
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Numerical ModelNumerical Model
• 2D finite-volume method• First-order scheme• Flux evaluated by Roe’s scheme• Non-Cartesian grids allowed
‘Soares Frazão S., 2002 PHD Thesis ’
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OverviewOverview
• Numerical Model• The ‘Isolated Building Benchmark’
– Numerical modelling– Numerical results– Sensitivity analysis
• The ‘Model City Benchmark’– Numerical modelling– Numerical results– Sensitivity analysis
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The ‘Isolated Building The ‘Isolated Building Benchmark’Benchmark’
• Numerical modelling (2-mesh grid)– Grid :
Square meshes
Quadrangular meshes
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The ‘Isolated Building The ‘Isolated Building Benchmark’Benchmark’
• Numerical modelling– Building neighbouring
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The ‘Isolated Building The ‘Isolated Building Benchmark’Benchmark’
• Numerical modelling– Grid mean size : 5 x 5 cm– CFL number : 0.9–Time duration : ± 2 h– CPU : AMD XP1800+ (128Mb)
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The ‘Isolated Building The ‘Isolated Building Benchmark’Benchmark’
• Numerical results
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0
0.05
0.1
0.15
0 5 10 15 20 25 30t [s]
Zw
ate
r [m
]
G1 - experimentG1 - numerical
The ‘Isolated Building The ‘Isolated Building Benchmark’Benchmark’
• Numerical results– Water level :
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The ‘Isolated Building The ‘Isolated Building Benchmark’Benchmark’
• Numerical results– Water level (t = 10 s) :
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The ‘Isolated Building The ‘Isolated Building Benchmark’Benchmark’
• Numerical results– Velocity field (t = 5 s) :
Numerical ExperimentalNoël, Spinewine 2003 - UCL
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The ‘Isolated Building The ‘Isolated Building Benchmark’Benchmark’
• Numerical results– Velocity Intensity (t = 5 s) :
Numerical ExperimentalNoël, Spinewine 2003 - UCL
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Water Level at G2
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0 5 10 15 20 25 30
t [s]
h [
m]
Experimentn = 0.008n = 0.01n = 0.012
The ‘Isolated Building The ‘Isolated Building Benchmark’Benchmark’
• Sensitivity analysis– Manning roughness coefficient
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The ‘Isolated Building The ‘Isolated Building Benchmark’Benchmark’
• Sensitivity analysis– Initial downstream water-depth
Water Level at G2
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0 5 10 15 20 25 30
t [s]
h [
m]
Experimenth0 = 0.0mh0 = 0.01mh0 = 0.02m
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OverviewOverview
• Numerical Model• The ‘Isolated Building Benchmark’
– Numerical modelling– Numerical results– Sensitivity analysis
• The ‘Model City Benchmark’– Numerical modelling– Numerical results– Sensitivity analysis
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical modelling (channelled)
Mesh XXX
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical modelling (10-mesh grid)
Mesh XXX
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical modelling (original)
Mesh XXX
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical modelling (10-mesh grid)
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical modelling– Topography reconstruction
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical modelling– Upstream reservoir
• Dimensions : unknown but seen on picture
about 1 meter of longitudinal length
lateral bed level similar to the bed level of upstream end of channel
• Best way to model : decrease bed level of feeding tank and fill it with water at rest
numerical crash at corner of reservoir
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical modelling– Upstream reservoir
• bed level of the upstream end of channel• Inlet introduced at the upstream end of the
prolonged channel
Inlet
Walls
Walls
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical modelling– Grid mean size : 2.5 x 2.5 cm– CFL number : 0.1– Time duration : ± 5h.– Computer : AMD XP1800+ (128Mb)
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical results– Test cases 1a & 1b (t = 20 s) :
Staggered layer :
- velocity decreased
- water level increased in the building layer
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical results– Test cases 2a & 2b (t = 20 s) :
Staggered layer :
- velocity decreased
- water level increased in the building layer
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical results– Test cases 3a & 3b (t = 20 s) :
Low inflow :
60 l/s
High inflow :
100 l/s
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical results– Test cases 4a & 4b (t = 20 s) :
Buildings as bed elevation (15 cm):
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical results– Test cases 4a & 4c (t = 20 s) :
High friction
(n = 10 s/m1/3):
- water lost in buildings
- maximum water level moves downstream and is a few decreased
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Sensitivity analysis– Downstream boundary condition
Water Level at G10
0
0.005
0.01
0.015
0.02
0.025
0 10 20 30 40 50 60
t [s]
h [
m]
average slopezero slope
WP3 : Flood PropagationWP3 : Flood PropagationComputation On The ‘Isolated Computation On The ‘Isolated
Building Test Case’ And The ‘Building Test Case’ And The ‘Model Model City Flooding Experiment City Flooding Experiment ’’
B. Noël, Soares S., Y. ZechUniversité catholique de Louvain
