Manuel Gómez

Experimental study of the stability of pedestrians exposed to urban pluvial flooding

AbstractnPopulations in urban environments are extremely mobile throughout the day and in various weather conditions; accounting for this pedestrian mobility and security becomes high importance. Research into the security and stability of the pedestrian environment under exposure to critical water flows provides an essential knowledge base with which the associated hazard unto them can be critically evaluated. This research seeks to analyse degrees of hazard in relation to persons exposed to high-volume rain events in urban areas. Several human trials of critical urban flows were conducted in order to determine the stability limits of pedestrians, crossing through a water flow in a real-scale physic model. Additionally, the critical first step from a dry footpath into fast-flowing water is considered and an assessment of the tested subjects’ emotional responses when entering and crossing flooded roadways was carried out. Results from this study are compared with various proposed human stability criteria as well as alternatives proposed in other written works. The presented study offers a stability threshold focused on shallow depths and high-velocity conditions, the most common urban flooding conditions.

Stability criteria for flooded vehicles: a state‐of‐the‐art review

Hazard conditions related to vehicular circulation are important in flood risk management. The knowledge of vehicles stability when those are exposed to flooding is crucial for an informed flood risk management in urban areas. After losing stability, the vehicle becomes buoyant and may be washed away with potential injuries and fatalities. Therefore, the analysis of the stability of vehicles exposed to flooding is important in order to make decisions to reduce the damages and hazards. Herein a comprehensive state-of-the-art on stability of vehicles exposed to flooding is presented. The different studies have been gathered in experimental, theoretical and guidelines proposals and all of them focusing on parked vehicles. There is a clear need to conduct more research in this field by testing a greater variety of models in order to offer a more general methodology to define stability threshold for any vehicle exposed to flooding. Nevertheless, in this work, it has been demonstrate that the most safety stability criterion for vehicles exposed to flooding up to now is the proposed in the Guide AR&R.

A new experiments-based methodology to define the stability threshold for any vehicle exposed to flooding

Abstract A vehicle exposed to flooding, after losing stability, becomes buoyant and may be washed away with potential injuries and fatalities. Such vehicles cause additional disruption to traffic that is already affected by flooding, which may lead to substantial indirect economic impact, especially in urban areas. Therefore, the analysis of the stability of vehicles exposed to flooding is important in order to make decisions to reduce damages and hazards. In this research, based on an experimental campaign that included a range of twelve car models, a new methodology to obtain the stability threshold for any real vehicle exposed to flooding is developed. A stability coefficient (SCmod) is derived with which the vehicles can be sorted by stability against water flows and their stability functions may be determined. The experiments were conducted with three different model scales (1:14, 1:18 and 1:24) and involved analysis of both friction and buoyancy effects, which made this the most comprehensive research study to date. This methodology enables the definition of a stable area in the flow depth-velocity domain for any real vehicle. A tool is provided that decision-makers in the field of urban flood risk management can employ and after defining a design vehicle they can obtain its corresponding stability threshold.

Experimental and Numerical Study of Stability of Vehicles Exposed to Flooding

Hazard conditions related to cars in urban areas circulation are important in flood riskmanagement. The definition of stability conditions for vehicles when they are in rban areas during flood events is extremely relevant in the hazard and risk studies related to floods. When we test the stability of a car, the vehicle can be buoyant and may be swept away creating potential injuries and even casualties. In this document a description and presentation of results of an experimental campaign developed at the UPC laboratory in Barcelona is presented. For all the cars tested it is possible to define their specific stability limits that can be used by municipalities in their hazard and risk studies. Moreover, same process has been repeated but in a numerical way, with a 3D commercial code (Flow3D). The results obtained showed the possibilities of 3D numerical model to complement physical tests as a virtual lab, with the only drawback of the high computational time, several days to reproduce few seconds of real time.

1D, 2D AND 3D MODELING OF A PAC-UPC LABORATORY CANAL BEND

The present study has been carried out to analyze the hydraulic behavior of the PAC-UPC canal, located in the Campus Nord of the Technical University of Catalonia. This constitutes a model of a real irrigation canal and, since its construction in 2003, it has been used for different studies and PhD dissertations related to irrigation canals and control algorithms. The snake-shaped canal, with the aim to minimize the space to be occupied, generates some bends along itself, where pronounced upraising water surface levels are produced. Even with a subcritical regime, clearly observable whose details require a complete analysis. In order to do these different types of approach considering a 1D, 2D and 3D analysis respectively have been proposed. Codes considered were: Hec-Ras (1D), Iber (2D) and Flow 3D, performing a comparative study of the results of each code. This comparison highlights the limitations of each one. As it was known previously, 3D results offer much more information about the flow behavior, even enabling the analysis of the recirculation zones and eddies formed in the z direction. The final results, after flow analysis, suggest possible improvement in the canal for future works and studies, regarding for instance the best location of the instrumentation (Level Sensors) or modifications about the geometry of the structure.