Simulation of the effects of canyon geometry on thermal climate in city canyons

Abstract

This paper presents some results from a numerical model of the wind and thermal climates, and the energy budgets, of city canyons. The model is capable of simulating spatial patterns of canyon energy budget components, subsurface and air temperature, and the components of the wind, as these are controlled by location, date (i.e. solar path), weather conditions in the overlying air mass, canyon geometry and orientation, surface radiative and aerodynamic properties, substrate thermal properties and building interior climate. Some model results are presented to illustrate the effects of changing canyon geometries on the model output. Geometries considered important in the literature are the ratio of the height of buildings to the width of the canyon and the ratio of the length of the canyon to height of the buildings. The variables considered here are building height, canyon width and canyon length. The effects of changing canyon geometry are demonstrated by changing the canyon length whilst keeping the other two variables constant; using a different width canyon whilst keeping the other two variables constant; and, using a different building height whilst keeping the other two variables constant.