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通过刚性模型风洞测压试验,对短边迎风和长边迎风时的矩形截面高层建筑表面风压特性及作用机理进行研究。对比了不同风向角下建筑表面风压分布及相关特性:短边迎风时,锥形涡是建筑侧面风压脉动的主要诱因,侧面脉动风压较大值出现在底边缘附近的瓣状区域内,该区域内风压互相关性显著;长边迎风时,旋涡脱落是导致建筑侧面风压脉动的主要因素,侧面吸力较大值集中在迎风前缘附近,且风压横向互相关性突出。基于风压时程的高阶矩,探讨了建筑表面风压非高斯脉动特性:短边迎风时,风压非高斯区位于迎风面角部、锥形涡作用区及尾流作用区;长边迎风时,非高斯区位于侧面迎风前缘附近的分离区。分析了建筑侧面脉动风压谱和风压相干性,结果表明:短边迎风时,建筑侧面风压脉动能量主要集中在低频段,风压强相干区域仅存在于迎风前缘附近;长边迎风时,旋涡脱落使得建筑侧面脉动风压谱和风压横向相干函数均在折减频率0.1处出现峰值,加之该频率所对应相位角接近0°,使得建筑侧面出现强烈且同步的风压脉动;短边迎风和长边迎风时锥形涡及旋涡脱落在建筑两侧诱导产生的风压脉动均为反相位,对结构抗风较为不利。
By the rigid model wind tunnel pressure test, the wind pressure characteristics and mechanism of the rectangular cross-section high-rise building with short-side upwind and long-side upwind are studied. The wind pressure distribution and related characteristics of building surface under different wind direction angles are compared. When the short side winds up, the conical vortex is the main cause of the wind pressure pulsation on the side of the building. The larger value of the side fluctuating wind pressure appears in the petal area near the bottom edge , The wind pressure cross-correlation is significant in this area; when the long-side windward, vortex shedding is the main factor leading to the wind pressure pulsation on the side of the building, the larger lateral suction concentration is near the windward front edge and the horizontal cross-correlation of wind pressure is prominent. Based on the higher moments of the wind pressure time-history, the non-Gaussian pulsation characteristics of the wind pressure on the building surface are discussed. When the short side winds up, the non-Gaussian wind pressure area is located on the windward corner, the cone- In the windward, the non-Gaussian zone is located in the separation zone near the leading edge of the windward side. The results show that when the short side winds up, the pulsating energy of the wind pressure on the side of the building is mainly concentrated in the low frequency band, and the coherent area of the wind pressure exists only in the vicinity of the front of the windward edge. When the long side winds up, The vortex shedding makes the side fluctuating wind pressure spectrum and the wind pressure lateral coherence function appear peak value at the reduced frequency of 0.1, and the phase angle corresponding to this frequency is close to 0 °, which makes the side of the building appear strong and synchronous wind pressure pulsation; And the long side windward conical vortex and vortex shedding induced in the building on both sides of the induced pressure pulsation are anti-phase, the wind is more adverse to the structure.