峡谷和垭口地形风场特征的CFD数值模拟

CFD-Based numerical simulation of wind field characteristics on valley and col terrain

摘要:

为获得峡谷和垭口地形的风场特征和典型位置的风加速效应，采用计算流体动力学(CFD)方法进行模拟计算，将计算得到的单山结果与风洞试验及规范进行对比以验证CFD计算的有效性，对峡谷和垭口地形进行数值模拟计算，分析峡谷和垭口在不同山脚间距时的加速效应，针对内侧山脚和山顶处的加速比给出设计建议.研究表明：山顶处加速比最大；山体横风切面的加速效应比顺风切面显著；CFD模拟与风洞试验结果吻合较好；山顶处，垭口地形风加速效应比峡谷和单山都大；内侧山脚加速比随着两山靠近而增大；内侧山脚处，峡谷地形的加速比小于规范下限，垭口地形在山间距小于一半山体底部直径、离山表面高度低于0.4倍山体高度时的加速比大于规范上限；山顶处的加速比在各种工况下均比较接近；不建议将山顶和垭口位置作为构筑物的选址地点.

Abstract:

To study the wind field characteristics of valley and col terrain and speedup effects in typical positions, Computational Fluid Dynamics (CFD) simulation methodology was employed. The results of an isolated hill obtained from CFD simulations, wind tunnel tests and codes were compared to validate the results of CFD simulation. Valley and col terrain were conducted by CFD. The speedup effects in typical positions of valley and col terrain were analyzed and some design suggestions were given for the top of hill and the inner side of hill bottom. The results show that the speedup effect on the top of hill is the most significant. The speedup effects on the cross-wind plane of an isolated hill are more significant than those on the along-wind plane. The results of CFD simulation match well with those obtained from wind tunnel test. The speedup effect on the top of col is more significant than those on valley and isolated hill. The speedup ratio at the inner side of hill bottom becomes greater with the decreasing distance between two hills. At the inner side of hill bottom under two adjacent hills condition, wind speedup ratio is less than the lower limit of the code for valley terrain and larger than the upper limit of that for col terrain when the distance between two hills is less than half diameter of hill bottom and the height above the hill is less than forty percent of hill height. The speedup effects on the top of hill are almost unchanged under various hill distance conditions. It is not commended to choose cols and tops of hills as the construction sites.