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中文核心期刊

分段吸气高层建筑减阻性能的数值研究

Numerical investigation of drag-reducing property for a high-rise building by subsection suction control

  • 摘要: 为减小高层建筑的风致阻力, 采用CFD方法研究了主动吸气控制下高层建筑模型的风载荷减阻性能,分析了竖向开孔位置、吸气孔高度和吸气速度等参数对减阻性能的影响,并详细展示流场,讨论吸气控制机理. 结果表明: 保持流量系数不变,增加吸气孔高度(或减小吸气速度)使得模型各表面的风压折减效率\eta_\rmPR, 阻力折减效率\eta_\rmDR和基底弯矩折减效率\eta_\rmMR增大,且只有\eta_\rmMR在较大吸气孔高度时超过1.0. 拟合了\eta_\rmDR和\eta_\rmMR关于吸气孔中心高度、吸气孔高度和吸气速度的经验公式,为分段吸气控制的应用提供参考. 基于最大风压折减效率和最小吸气功率,比较了各分段吸气模型和全高吸气模型的减阻性能,发现全高吸气模型的减阻性能优于分段吸气模型.可在高层建筑中上部设置吸气装置来减小基底弯矩或改善其局部风压特性.

     

    Abstract: As a result of theextensive utility of high-strength and light-weight materialsin construction, high-rise buildings tend to be very vulnerable tothe wind loads, and the wind-resistance design has graduallybecome the dominate factor in structural designs. To reducethe wind-induced drag force and improve the wind-resistanceperformance of a high-rise building, the active suction controlis proposed to investigate the drag-reduction property vianumerical simulation. Effects of the slot locations along theheight, the suction heights and suction velocities on thedrag-reduction property are analyzed. Moreover, the detailed flowfield is presented to discuss the mechanism of the suction control. Theresults indicate that, as the suction height increases,coefficient of pressure reduction, coefficient of drag reductionand coefficient of along-wind base moment reduction will increaseunder the same suction velocity, and their efficiencies(efficiency of pressure coefficient reduction \eta_\rmPR,efficiency of drag reduction \eta_\rmDR and efficiency ofalong-wind base moment reduction \eta_\rmMR) will decreaseuntil 1.0. On the other hand, the \eta_\rmPR (\eta_\rmDR or \eta_\rmMR) will increase along with theincrement of suction height under the same flux coefficient, andonly the \eta_\rmMR will be greater than 1.0 at largersuction height. Based on the analysis above, formulae of the\eta_\rmDR and \eta_\rmMR versus the slot location,suction height and suction velocity are regressed to be referredfor practical application of subsection suction on the high-risebuilding. Lastly, comparison of the drag-reduction property of thesubsection suction models and all-height suction model areperformed based on the maximal drag-reduction efficiencies and theminimal power consumed, and the latter is superior to the formers.However, the subsection suction is still practical, as it canbe used on upside of high-rise buildings to reduce the basemoment or improve the local wind pressure characteristics.

     

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