Numerical analysis of flow field and flood risk in solid urban block street intersections

Document Type : Research Article

Authors

1 Department of Civil Engineering, Faculty of Engineering, University of Mohaghegh Ardabili

2 University of Mohaghegh Ardabili

3 Civil Engineering, Faculty of Engineering, Mohaghegh Ardabili University, Ardabil, Iran

10.30482/jhyd.2023.399985.1650

Abstract

Floods can cause significant damage to goods and people, particularly in densely populated urban areas with high asset values. Flood risk is typically assessed using flow depth, flow velocity, and water level parameters (de Moel et al., 2009). Meja-Morales et al., (2021) investigated the impact of flow exchanges between a porous urban block and surrounding streets and found that porosity significantly affects urban flood flow characteristics. In another study, Meja-Morales et al., (2023) examined the effect of flow instability and open areas in urban blocks on key flood characteristics and reported that the instability level of incoming hydrographs greatly affects the volume of flood water stored in urban blocks. This research aims to evaluate the distribution of flow depth, velocity, and flow patterns in non-porous urban block streets by considering changes in stable inflow. The study seeks to understand multidirectional flow paths caused by the street network and develop a flood risk map for humans using Flow3D software. The validation results of the numerical model showed that the turbulence model had the highest correlation with the laboratory model, with a relative error of 3% and 6.8% for the velocity profile near the water surface and averaged velocity at depth, respectively. In all models, the right and upstream streets had the highest and lowest depth, speed, and human stability number, while the downstream street had the largest range of flood parameters, with 2 to 3 times the average speed and 3 to 4 danger zones for pedestrians. Increasing the flow rate at Inlet 1 for a constant flow rate at inlet 2 increased the flooding characteristics of the right and downstream streets while decreasing the speed in the left street. Conversely, increasing the flow rate at Inlet 2 for a constant flow rate at Inlet 1 increased the flooding characteristics of the left street, decreased the speed in the right and downstream streets, and had minimal effect on the flood characteristics of the upstream street.

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Articles in Press, Accepted Manuscript
Available Online from 03 September 2023
  • Receive Date: 08 June 2023
  • Revise Date: 22 July 2023
  • Accept Date: 21 August 2023