不同长宽比矩形高层建筑的分离再附流动特性

为研究边界层紊流特性、断面长宽比和空间位置等因素与矩形高层建筑分离再附流动特性之间的关联,通过不同长宽比矩形建筑模型的同步测压试验,获取不同工况下的表面风压实测数据;分析了影响矩形建筑三维分离再附流动和分离区长度演化规律的多种因素,探讨了大尺度紊流下矩形高层建筑的非定常气动力与分离再附流动特性的内在关联;定量给出了平均分离区长度在竖向的分布规律.研究结果表明:紊流风场的积分尺度与建筑特征尺寸的比值关系会影响分离再附流动和气动力特性的试验精准度,最大偏差可达约24%;边界层紊流的干扰导致分离剪切层曲率增大,加强了对分离区的卷夹作用,稳定再附将发生在长宽比为2时;平均分离区长度在竖向方向逐渐增大,并依据试验结果给出了高层建筑侧面风压取值的修正建议.

Separation-Reattachment Flows Characteristics of Rectangular High-Rise Buildings with Different Side Ratios

To study the influents of turbulence characteristics, side ratio, and spatial position on the separation-reattachment flows of rectangular high-rise buildings, Firstly, the measured data of surface pressure under different conditions were obtained by synchronous pressure tests of rectangular building models with different side ratios. Secondly, various factors affecting the evolution of the three-dimensional separation-reattachment flows and the mean separation length of rectangular high-rise buildings were analyzed, the intrinsic correlation between the unsteady aerodynamic forces and the separation-reattachment flows of rectangular buildings under large-scale turbulences was discussed. Finally, the mean separation lengths in the vertical direction were given quantitatively. The results show that the ratio of the turbulence integral scale to the feature size of the building affects the test accuracy of separation-reattachment flows and aerodynamic characteristics, with a maximum deviation of about 24%. The interference of incoming turbulence causes the curvature of the separated shear layers to increase, and enhances the entrainment of the uniform-shear flows in the separation zone, the stable reattachment will occur when the side ratio is 2. The mean separation length of the rectangular high-rise building gradually increases in the vertical direction, correction suggestions for predicting the lateral wind pressure of high-rise buildings are also given based on the test results.