山地风速地形修正系数沿山坡的详细插值分布

Detailed Interpolation Distribution of Hilly Wind Topographic Factor along Hillside

为研究山地风速地形修正系数η沿各向山坡的详细分布,对两座缩尺比为1∶300的具有不同坡度的余弦型单体山峰模型进行了风洞试验,获得了η沿迎、背、侧风坡面的详细分布.采用CFD软件Fluent建立数值模型,并将其计算结果与风洞试验结果进行对比,验证了数值模型的正确性.对具有不同高度（H=90~500m）,不同坡度（tanα=0.13~0.5）和不同形状（余弦型、高斯型、抛物线型）的山体进行了数值模拟,拟合了山坡任意位置的η值建议计算公式,并与各国规范进行对比.结果表明,相对于现有水平向线性插值模型,根据山脚和山顶的η值,以计算点距山脚点的垂直距离h为自变量的竖向线性插值模型更能安全、合理、简便地估计山坡任意点的η值.侧风坡面的加速效应对于η取值起控制作用;侧风坡脚的η值可相对于迎、背风坡脚分别大61.89%和94.09%,最大可达1.2.

Building structures are randomly distributed along the hillside, thus the detailed distribution of the topographic factor along hillside is of great importance to the wind load prediction of building structures in hilly terrain. To investigate the detailed distribution of the topographic factor along the hillside, wind tunnel tests were conducted on two hill models with different slopes, both of which were scaled to 1 ： 300 with a cosine section. The detailed distribution of the topography factor along the upwind slope, downwind slope, and side slope was obtained. Numerical models, which were verified by the wind tunnel testing results, were built to investigate the detailed distribution of the topographic factor of the hills with different heights （H=90-500 m）, slopes （ tan a =0. 13-0.5）, and shapes （Cosine shape, Gaussian shape, Parabolic shape）. Furthermore, it was employed to deduce the calculation formula of the topographic factor, which were also compared with several national codes. Research results show that, based on the topographic factor at the hill foot and the hill top, a particular topographic factor at optional position can be obtained more safely, reasonably and simply by using vertical linear interpolation depending on the height of the calculated point rather than the horizontal linear interpolation. It was found that the topographic factor of the side slope was the control one in the prediction of the topographic factors, where the topographic factor at the foot of the side slope was respectively 61.89% and 94. 09% greater than that of the upwind slope and the downwind slope, respectively, and the value reached up to 1.2.