Analysis of Underground Flooding Phenomena and Decision Support Using 3D CFD Simulation

The frequency of underground flooding has been increasing due to the intensification of extreme rainfall events and rapid urbanization. Three-dimensional (3D) CFD simulations enable the analysis of complex flow behaviors that are difficult to capture using two-dimensional (2D) models, particularly in areas with large hydraulic gradients, where turbulent and vortical flows frequently occur. In addition, the CFD simulations allow for detailed representation of structural effects, including buildings, underground facilities, and flood protection structures such as flood barriers.

In this study, an underground parking facility within a multi-use building is selected as a case study to analyze flood hydraulics in underground spaces. The flooding process is analyzed in both spatial and temporal dimensions to identify the onset time of inundation and the progression of flood depths. Based on this analysis, evacuation times are estimated to support decision-making for emergency response and flood risk management in underground facilities.(This research was supported by a grant(RS-2025-02313776) of the Regional Customized Disaster-Safety R&D Program funded by Ministry of Interior and Safety(MOIS, Korea).)