Seite - 80 - in Intelligent Environments 2019 - Workshop Proceedings of the 15th International Conference on Intelligent Environments

3.2. The simulation setup for COSMO Figure 2. Numerical settings of COSMO with the boundary conditions. A numerical domain for an idealised canopy with street aspect ratio of 1 was created for the testing of the mathematical model, i.e. dynamical coupling between RANS based CFD and urban energy balance modelling described in chapter two. The testing involved a comparison between calculated and measured air temperatures from COSMO (see, figure 2). Air temperature distributions were calculated for 24 hours. They were extracted from the last 24 hours of a 48 hours simulation. Time steps were set for five minutes each. The domain size is 28.50 metres x 28.50 metres x 11.40 metres. The grid resolution is set at 30 centimetres x 30 centimetres x 30 centimetres. It includes 81 concrete blocks. Every single block measures 1.5 metres x 1.5 metres x 1.5 metres, the same as COSMO. The weather data for September 6 th 2009 was obtained from AMEDAS at Kumagaya meteorological weather station in Saitama north of Tokyo. This day was a hot day and temperatures exceeded 29.9°C. This data lacked radiation information. Therefore, a Japanese radiation model was used to complete the data. The boundary conditions for the vertical profiles of wind, potential temperature, humidity, pressure, kinetic energy, dissipation rate of the kinetic energy and wet and dry air molecules were created so as to initiate calculations by considering both the weather data discussed above and the grid’s height. 3.3. Calculations vs Measurements Comparison A very high time resolution data was measured. For the comparative study and the testing, this data was averaged over 10 minutes and 30 minutes. There was no major difference between the two and the 10 minutes’ data was taken into account for the testing. In general, good agreements were found between measured and calculated air temperatures and some little discrepancies between the ground and above the canopy were deduced. Air temperature patterns were however following the same trends. M.Bakkali andY.Ashie /RANSModelling forLocalClimates,EnergyUseandComfortPredictions80