Numerical Analysis of Solar Radiation Effects on Flow Patterns in Street Canyons

Abstract

A three dimensional computational fluid dynamics (CFD) model based on the Reynolds-averaged Navier-Stokes equations with the standard k-ɛ turbulence scheme is applied to simulate the influence of thermal effects on air flow pattern, pressure distribution and air exchange in a regular street canyon with different thermal conditions and different background wind speeds. The results show that the thermal conditions can greatly affect the flow patterns inside the street canyon, and an impact factor w is defined to discuss the influence of thermal conditions on the static pressure distribution around the buildings. The value of w decreases with the increase of the wind speed for both upwind and downwind buildings. When the wind speed reaches a critical value (i.e., Vc), the influence of thermal effects on the pressure distributions near the buildings can be ignored. The air exchange rate in the canyon remains unchanged when the wind speed is above Vc.