WP3 : Flood Propagation Computation On The ‘Isolated Building Test Case’ And The ‘Model City...
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Transcript of WP3 : Flood Propagation Computation On The ‘Isolated Building Test Case’ And The ‘Model City...
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
IMPACT - 3rd Workshop Novembre 2003
3
OverviewOverview
• Numerical Model• The ‘Isolated Building Benchmark’
– Numerical modelling– Numerical results– Sensitivity analysis
• The ‘Model City Benchmark’– Numerical modelling– Numerical results– Sensitivity analysis
IMPACT - 3rd Workshop Novembre 2003
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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 ’
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
IMPACT - 3rd Workshop Novembre 2003
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The ‘Isolated Building The ‘Isolated Building Benchmark’Benchmark’
• Numerical modelling (2-mesh grid)– Grid :
Square meshes
Quadrangular meshes
IMPACT - 3rd Workshop Novembre 2003
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The ‘Isolated Building The ‘Isolated Building Benchmark’Benchmark’
• Numerical modelling– Building neighbouring
IMPACT - 3rd Workshop Novembre 2003
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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)
IMPACT - 3rd Workshop Novembre 2003
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The ‘Isolated Building The ‘Isolated Building Benchmark’Benchmark’
• Numerical results
IMPACT - 3rd Workshop Novembre 2003
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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 :
IMPACT - 3rd Workshop Novembre 2003
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The ‘Isolated Building The ‘Isolated Building Benchmark’Benchmark’
• Numerical results– Water level (t = 10 s) :
IMPACT - 3rd Workshop Novembre 2003
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The ‘Isolated Building The ‘Isolated Building Benchmark’Benchmark’
• Numerical results– Velocity field (t = 5 s) :
Numerical ExperimentalNoël, Spinewine 2003 - UCL
IMPACT - 3rd Workshop Novembre 2003
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The ‘Isolated Building The ‘Isolated Building Benchmark’Benchmark’
• Numerical results– Velocity Intensity (t = 5 s) :
Numerical ExperimentalNoël, Spinewine 2003 - UCL
IMPACT - 3rd Workshop Novembre 2003
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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
IMPACT - 3rd Workshop Novembre 2003
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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
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
IMPACT - 3rd Workshop Novembre 2003
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical modelling (channelled)
Mesh XXX
IMPACT - 3rd Workshop Novembre 2003
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical modelling (10-mesh grid)
Mesh XXX
IMPACT - 3rd Workshop Novembre 2003
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical modelling (original)
Mesh XXX
IMPACT - 3rd Workshop Novembre 2003
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical modelling (10-mesh grid)
IMPACT - 3rd Workshop Novembre 2003
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The ‘Model City Benchmark’The ‘Model City Benchmark’
• Numerical modelling– Topography reconstruction
IMPACT - 3rd Workshop Novembre 2003
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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
IMPACT - 3rd Workshop Novembre 2003
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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
IMPACT - 3rd Workshop Novembre 2003
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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)
IMPACT - 3rd Workshop Novembre 2003
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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
IMPACT - 3rd Workshop Novembre 2003
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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
IMPACT - 3rd Workshop Novembre 2003
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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
IMPACT - 3rd Workshop Novembre 2003
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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):
IMPACT - 3rd Workshop Novembre 2003
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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
IMPACT - 3rd Workshop Novembre 2003
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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