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

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.