某复杂山体的三维风场特征研究

为获得某复杂山体的三维风场特征,采用基于眼镜蛇测量仪的风洞试验方法进行研究。分析各风向角下水平风加速比和竖向风速占比的分布特征,将典型风向的水平风加速比与各国规范进行比较,最终提出复杂山体三维风场的设计建议。研究表明:山顶在各风向角下均存在显著的水平风加速效应;山腰和山脚在侧风风向存在较显著的水平风加速效应;风洞试验结果与美国规范非常接近,中国规范偏保守;最大竖直向风速发生在山腰位置,其中向上竖向风速发生在迎风方向,向下的竖向风速发生在背风方向;规范中的水平风速只针对迎风情况,并不能考虑全风向尤其是侧风向的来流;建议对重要的山体构筑物采用风洞试验方法获得其三维风场。

A study on three-dimensional wind field characteristics of a complex hill

In order to investigate three-dimensional wind field characteristics of a complex hill, a wind tunnel testing method using a Cobra probe was employed.The distribution characteristics of horizontal speed-up ratios and vertical velocity proportions under various wind azimuths were analyzed.The wind speed-up ratios under typical wind azimuths were compared with those regulated in various countries' Codes.Finally, a design proposal to three-dimensional wind field of a complex hill was suggested.Results show that a significant horizontal speed-up effect can be found at the top of the hill under all wind directions.A relatively significant horizontal speed-up effect can be found on the slope and at the foot of the hill in the crosswind direction.The wind tunnel test results are very close to those regulated in the American Code, while the data regulated in the Chinese Code is the most conservative.The maximum vertical wind speed occurs on the slope of hill, where the upward vertical velocity takes place in the windward direction and downward vertical velocity takes place in the leeward direction.The horizontal wind velocity regulated in the Codes is only referred in the windward situation, while the horizontal speed-up effect in all wind directions cannot be considered, especially in the crosswind direction.A wind tunnel testing method is recommended to obtain three-dimensional wind field characteristics for important constructions built on a complex hill.