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

As a result of the extensive utility of high-strength and light-weight materials in construction, high-rise buildings tend to be very vulnerable to the wind loads, and the wind-resistance design has gradually become the dominate factor in structural designs. To reduce the wind-induced drag force and improve the wind-resistance performance of a high-rise building, the active suction control is proposed to investigate the drag-reduction property via numerical simulation. Effects of the slot locations along the height, the suction heights and suction velocities on the drag-reduction property are analyzed. Moreover, the detailed flow field is presented to discuss the mechanism of the suction control. The results indicate that, as the suction height increases, coefficient of pressure reduction, coefficient of drag reduction and coefficient of along-wind base moment reduction will increase under the same suction velocity, and their efficiencies (efficiency of pressure coefficient reduction η_PR, efficiency of drag reduction η_DR and efficiency of along-wind base moment reduction η_MR) will decrease until 1.0. On the other hand, the η_PR (η_DR or η_MR) will increase along with the increment of suction height under the same flux coefficient, and only the η_MR will be greater than 1.0 at larger suction height. Based on the analysis above, formulae of the η_DR and η_MR versus the slot location, suction height and suction velocity are regressed to be referred for practical application of subsection suction on the high-rise building. Lastly, comparison of the drag-reduction property of the subsection suction models and all-height suction model are performed based on the maximal drag-reduction efficiencies and the minimal power consumed, and the latter is superior to the formers. However, the subsection suction is still practical, as it can be used on upside of high-rise buildings to reduce the base moment or improve the local wind pressure characteristics.