The Influence of the City in Urban Heat Island Circulation

摘要

A new upscaling approach called city-scale computational fluid dynamics (CSCFD) is used to simulate the influence of the city when urban heat island circulation (UHIC) occurs.In the CSCFD approach,conventional CFD are modified to include the mesoscale (～10 km) phenomenon,and the city is treated as porous media instead of fully-resolved to reduce computational source.The influence of the city is significant.Under zero background wind,when the UHIC occurs,the velocity in the city decreases due to the blockage of the building clusters,but it still remains about 1m/s,which is important for building and urban design when there is no synoptic wind.The porous city also increases the reserve region height,reduces the mixing height due to friction,and introduces multiple upward plumes.