Author(s): M. Velickovic; S. Soares-Frazao; Y. Zech
Linked Author(s):
Keywords: Dam-break flow; Steady flow; Porosity model; Urban area; Experiments
Abstract: In the prediction of water levels and velocities in cities subject to severe floods, various levels of accuracy might be required: for detailed results inside the city a full 2D model representing streets and buildings is preferable; but such a detailed model is useless to assess the flow pattern outside the city. In the latter case, where the whole city is considered as an obstacle to the flow, a porosity model may be suitable, as far as a drag coefficient is used to account for additional head losses. Laboratory tests were conducted under two types of flow conditions: steady and dam-break flow. A set of 5 × 5 square blocks were used to represent the buildings. The streets were either aligned, or presenting an angle of 22.5° with the main flow directions. It was observed that the drag coefficient was practically insensitive to the transient character of the flow but much more to the alignment.
Year: 2011