The configuration of urban street-canyons, especially the ratio of the height of the buildings to the street width (H/W) and length to width (L/W), plays an essential role in directing and dispersion of wind flow and consequently affects changes in air temperature and urban heat islands (UHI). Despite many studies examining the aspect ratio of street-canyons, failure to follow these ratios from a specific order and organization and the lack of an optimal range for urban design is a gap seen in these studies. In addition, if the H/W exceeds a certain range, the results will change significantly and sometimes in reverse. Therefore, this paper simulates a residential town using CFD calculations in ANSYS-CFX 18. In two different scenarios (each scenario has four modes), wind flow and temperature changes were evaluated to find the optimal value of H/W and L/W. The analysis of changes in the three factors of wind velocity, temperature, and pressure show that the ratios H/W =1 and L/W=2 are the most suitable conditions for temperature reduction and UHI control. In addition, a sensitivity analysis confirms the generalizability of the obtained ratios to other fields with different temperature conditions and wind speeds.
