CFD simulations of the effect of evaporative cooling from water bodies in a micro-scale urban environment: Validation and application studies

Computational fluid dynamics (CFD) simulations of the evaporative cooling effect from water surfaces in a micro-scale urban environment were evaluated via validation and application studies with various configurations. First, the basic ability of CFD simulations to reproduce the evaporative cooling on a simplified small-scale water surface in a boundary layer was investigated. Next, the prediction accuracy of the vapor transport mechanism from a water surface within an array of building was evaluated. It was confirmed that the vapor transport mechanism influenced by the complex wind flow around buildings could be reproduced by the current CFD code within a given accuracy. Finally, a numerical analysis that combined CFD and radiative heat transfer analysis was conducted for predicting the thermal environment around an actual residential neighborhood with a pond. The results were compared to experimental data. The experimental air temperature distribution around the pond was qualitatively reproduced via CFD. The maximum temperature decrease induced by the water surface was approximately 2 °C at the pedestrian level. For a wind velocity of approximately 3 m/s at a height of 10 m, the effect of the evaporative cooling propagates downwind over an unobstructed distance of 100 m.