Combining terrestrial laser scanning and computational fluid dynamics for the study of the urban thermal environment

• 3D model of an outdoor space is developed using Terrestrial Laser Scanners.
• The 3D model is analyzed using Computational Fluid Dynamics.
• The outdoor comfort is calculated.
• The contribution of cool pavements is analyzed.

Public spaces located in urban areas constitute a significant vital component of the city's organism, whilst contributing to the mitigation of phenomena such as urban heat island serving as a regulator of urban bioclimatic conditions. In recent years a multiplicity of methodologies have been deployed that enable the 3D modeling of the built environment and the individual study of prevailing bioclimatic conditions in areas such as public spaces, using software and computational techniques.The aim of the present study is to combine Terrestrial Laser Scanners (TLS) and aerial ortho-photography with computational fluid dynamics (CFD) to study the thermal characteristics of the outdoor space. For the specific analysis a public square in the city of Chania, Crete, Greece, is selected as case study. The TLS are used for the creation of detailed 3D models that are then forwarded to the CFD. The study of the urban environment is based on two scenario analyses in order to evaluate the role of materials to the air temperatures and predict the air flow velocities that influence the thermal comfort conditions in the area of interest. The evaluation of bioclimatic indices showed a significant improvement regarding the thermal comfort conditions prevailing. The TLS method provides a suitable format of the study area while the CFD approach enables a more detailed analysis taking into account more specific parameters that shape the microclimate of the square, such as radiation, turbulence models for the study of the flows, with the aid of a well-defined computation grid.