通过理论分析与风洞试验研究背景孔隙对开孔结构风致内压响应的影响。利用伯努利方程导出了考虑背景孔隙的内压传播方程,通过数值算例分析了层流与紊流中背景孔隙的附加阻尼特性,并给出了紊流风场中背景孔隙对内压脉动影响的量化指标。设计制作了具有不同开孔率和背景孔隙率的低层建筑刚性模型进行边界层风洞试验,采用同步测压方法捕捉了内压稳态响应,验证了内压的空间完全相关性,试验得到的均方根内压系数与理论分析结果较为相符。研究结果表明本文推导的方程能准确的预测背景孔隙对风致内压响应的影响,能为工程抗风设计提供有效的理论依据。
Theoretical analysis and wind tunnel tests were carried out to study the influence of background porosity on wind-induced internal pressure response for structures with openings. The governing differential equation for structure with single dominant opening considering background porosity was derived using the unsteady-isentropic form of the Bernoulli equation. Numerical examples were provided to study the additive damping caused by background porosity in laminar and turbulent flow, also presented a quantitative index on the influence of the fluctuating internal pressure. A series of low-rise building models with various opening ratios and background porosity were designed and wind tunnel tests were conducted. Internal pressure coefficient time histories obtained from these tests confirms "the full correlation of internal pressure response, and the test results agree well with the theoretical analysis. It is shown that background porosity reduces internal pressure fluctuation and this effect can be predicted accurately by using the governing differential e.quation deduced in this paper.