下击暴流作用下的开洞超高层建筑风致内压及净压

Wind-induced Internal Pressure and Net Pressure of a Super High-rise Building with Opening Under Downburst Action

通过自制发生装置在大气边界层风洞中模拟下击暴流风场,对典型开洞高层建筑进行内外压风洞试验,研究下击暴流和B类风场作用下开洞高层建筑的内压、净压特性和内压增益函数,进一步识别孔口特征参数,并将内压极值的理论计算结果与试验结果进行对比分析。结果表明,随风向角的增大,内压系数平均值和极值均先减小后增大。两侧面的净压极值最大,易发生风致破坏。开洞面由于内外压相关系数为正值,内外压作用相互抵消,其净压最小。在50°斜风向的来流作用下,内压增益幅值远大于其他风向角下的结果,且在Helmholtz共振频率处的内压能量显著增大。除70°~100°风向角外,其他风向角下内压系数极值的理论值与试验值吻合良好。

Wind field of downburst was simulated in the atmospheric boundary layer wind tunnel by a self-made generator,and synchronous pressure measurements on the internal and external pressures of a typical high-rise building with an opening were conducted.The characteristics of internal pressure and net pressure as well as the internal pressure gain function were investigated in the terrain catergories downburst and B.Furthermore,orifice parameters were identified,and the theoretical calculation results of peak internal pressure were compared with the corresponding experimental results.Results show that both the mean and peak internal pressure coefficients decrease first and then increase with the increase of wind direction angle.Peak net pressures on both side-walls are the largest,which will easily lead to damage of side-walls.However,net pressure on the front wall with opening is the smallest due to the positive correlation between internal and external pressures.Besides,the amplitudes of internal pressure gain function in the wind direction of 50°are much larger than those in other wind directions,and the internal pressure energy at the Helmholtz resonance frequency is also significantly larger than that at other frequencies.Except for the wind direction angles of 70°~100°,the theoretical values of peak internal pressure coefficient are in good agreement with the experimental values.