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

IMPACT - 3rd Workshop Novembre Overview 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 Overview 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 Numerical 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 Overview 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 The ‘Isolated Building Benchmark’ Numerical modelling (2-mesh grid) – Grid : Square meshes Quadrangular meshes

IMPACT - 3rd Workshop Novembre The ‘Isolated Building Benchmark’ Numerical modelling – Building neighbouring

IMPACT - 3rd Workshop Novembre The ‘Isolated Building 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 The ‘Isolated Building Benchmark’ Numerical results

IMPACT - 3rd Workshop Novembre The ‘Isolated Building Benchmark’ Numerical results – Water level :

IMPACT - 3rd Workshop Novembre The ‘Isolated Building Benchmark’ Numerical results – Water level (t = 10 s) :

IMPACT - 3rd Workshop Novembre The ‘Isolated Building Benchmark’ Numerical results – Velocity field (t = 5 s) : NumericalExperimental Noël, Spinewine UCL

IMPACT - 3rd Workshop Novembre The ‘Isolated Building Benchmark’ Numerical results – Velocity Intensity (t = 5 s) : NumericalExperimental Noël, Spinewine UCL

IMPACT - 3rd Workshop Novembre The ‘Isolated Building Benchmark’ Sensitivity analysis – Manning roughness coefficient

IMPACT - 3rd Workshop Novembre The ‘Isolated Building Benchmark’ Sensitivity analysis – Initial downstream water-depth

IMPACT - 3rd Workshop Novembre Overview 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 The ‘Model City Benchmark’ Numerical modelling (channelled) Mesh XXX

IMPACT - 3rd Workshop Novembre The ‘Model City Benchmark’ Numerical modelling (10-mesh grid) Mesh XXX

IMPACT - 3rd Workshop Novembre The ‘Model City Benchmark’ Numerical modelling (original) Mesh XXX

IMPACT - 3rd Workshop Novembre The ‘Model City Benchmark’ Numerical modelling (10-mesh grid)

IMPACT - 3rd Workshop Novembre The ‘Model City Benchmark’ Numerical modelling – Topography reconstruction

IMPACT - 3rd Workshop Novembre 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 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

IMPACT - 3rd Workshop Novembre 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 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 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 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 The ‘Model City Benchmark’ Numerical results – Test cases 4a & 4b (t = 20 s) : Buildings as bed elevation (15 cm):

IMPACT - 3rd Workshop Novembre The ‘Model City Benchmark’ Numerical results – Test cases 4a & 4c (t = 20 s) : High friction (n = 10 s/m 1/3 ): - water lost in buildings - maximum water level moves downstream and is a few decreased

IMPACT - 3rd Workshop Novembre The ‘Model City Benchmark’ Sensitivity analysis – Downstream boundary condition

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