Mirjana Velickovic's PhD Thesis

Floods are natural disasters that can have huge economical consequences and affect an increasing number of people throughout the world. In order to mitigate risks of flooding, it is necessary to have a good knowledge of the inundation extent and the main flow direction for an extreme event. This requires reliable numerical models that can predict the water depth and the water velocity. The presence of urban areas constitutes a challenge in the modeling of flood propagation because the street scale is an order of magnitude smaller than the scale of the undeveloped domain. To avoid expensive mesh refinement in such urban areas, a classical solution consists in adopting a simplified model in the urban areas.
This dissertation is devoted to the development of a simplified modeling approach consisting in representing an urban area as a porous medium in which the pores would be the streets and the solid matrix the buildings. The governing equations are developed following the volume averaging technique. The energy losses in the urban medium and the directional effects due to the alignment of the buildings are accounted for in the closure model by drag and dispersion terms. Numerical experiments in periodic media show that the water flows preferentially in the street direction and that wider streets oppose less resistance to the flow. Finally, the new model is validated against laboratory experiments of steady flow and dam break-like flows through an idealized urban district made of 5 × 5 blocks representing the buildings.

Jury:
Professeur Sandra SOARES-FRAZAO (UCL), Promoteur
Professeur Jean-François REMACLE (UCL), Président
Professeur Yves ZECH (UCL), Secrétaire
Professeur François DUPRET (UCL)
Professeur Vincent GUINOT (Université Montpellier 2, France)