Numerical coupling model to compute the microclimate parameters inside a street canyon Part I: Methodology and experimental validation of surface temperature

This decade has been marked by a fast development of software and hardware systems. The numerical simulation models of microclimate provide much better information and analysis capabilities about thermodynamic behaviors for many ranges of urban configurations. The street canyon forms a basic geometric unit of the built environment. The morphology and materials that make up the canyons of a city greatly influence the urban climate. In the first step, this paper presents a methodology for a numerical approach based on the coupling between the CFD Model, Code_Saturn (software developed by EDF1) and the thereto-radiative model, Solene (software developed by CRENAU(2) laboratory). In the second step, the surface temperatures output results of coupled simulations are compared with the in situ data obtained during the EM2PAU(3) campaign. The experimental configuration was conducted using two lines of steel containers buildings composing one street canyon. The simulated surface temperatures are compared with the measurements for a full week period representative of relatively warm period with varied weather conditions. The simulation results show a good coherence with measurements during daytime for all surfaces as well as disagreements during nighttime for the street due partly to inappropriate choice of physical properties of street canyon materials.