Impact of complex relief on heat transfer in urban area

Abstract

The paper presents results of a laboratory modeling of heat transfer processes in the idealized urban landscape conditions. As an experimental model, we used a three-dimensional layout of the central part of Perm city (the area of five square kilometers) at the scale of 1:4000. The estimation of governing parameters was done using eddy transfer coefficients which are common for the atmospheric boundary layer. The process of cooling of the city model surface after prolonged heating by infrared radiation was studied. The key issue is the time dependence of the surface temperature on the type of urban structure. We focused on the influence of building density and artificial relief on the cooling process of the layout surface. Two separate stages of cooling were revealed, namely, relatively short period of a fast cooling and long time relaxation period. On the base of correlation coefficients it was shown that a buildings density has substantial influence on the fast stage and during this stage the correlation coefficient is larger than 0.4. The correlation at the late stage of cooling is weak. The duration of the fast cooling stage shows even stronger correlation (above 0.5) with building density.