热浮力对不同高宽比街道峡谷内流场影响研究

Study on the Impact of Thermal Buoyancy on the Flow Field in Street Canyons with Different Aspect Ratios

采用二维街道峡谷数值模型,研究墙体加热、不同高宽比、风速条件下对街道峡谷内部流场的影响。结果表明:街道峡谷的高宽比、来流风速及墙体的受热方式对峡谷内部流场影响显著;受热墙体对峡谷内部流场影响与峡谷高宽比及来流风速大小密切相关;背风面受热可加强内部对流;迎风面受热在低风速时有利于置换峡谷内部空气;底部受热可以在局部范围内加强内部对流;三种边界面的受热方式在来流风速大的时候对流场影响有限;高宽比越大,峡谷内部流场越复杂。

Numerical calculation was adopted to study the flow field in street canyon under different aspect ratios and wind speeds.The results showed that aspect ratios,wind speed and wall heating had significant effect on the flow field inside the canyon.Leeward-wall heating could accelerate internal convection inside the canyon.Windward-wall heating was conducive to displacement ventilation.Ground heating could enhance internal convection locally.Three heating ways had little impact on the flow field under the high incoming wind speed.The greater the aspect ratios,the more complex the flow field in the canyon.The research results implied a good practical reference value for urban planning.