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A full-scale measurement of wind characteristics atop a high-rise building (with a height of 115 m) was conducted during the passage of Typhoon Sarika on 18 October 2016. Wind field characteristics, wind speed, and wind direction atop the building were recorded synchronously, and turbulence intensity, turbulence integral scale, gust factor, and power spectrum were investigated. Meanwhile, the time and frequency domain characteristics of the wind field were analyzed. The stationarity test results of Typhoon Sarika at different time steps are researched in a runs test. And the time-frequency analysis of non-stationary samples of fluctuating wind speed are conducted by wavelet transform, the measured data are valuable for the wind-resistant design of high-rise buildings in typhoon-prone regions. [ABSTRACT FROM AUTHOR]

On 18 October 2016, the wind-induced effects of a high-rise building with square section was measured by the monitoring system in Haikou of China during Typhoon Sarika. The wind characteristics atop the building and the time-history responses of the translational and rotational accelerations on different floors were measured by the monitoring system; the first three modal parameters were identified according to the measured acceleration. The results show that the combinations of the cross spectral density function, phase spectrum, and coherence function can clearly judge the phase of the measured floors in the frequency resonance area as well as its modal frequencies at the first three orders. The modal frequencies at the first three orders decrease linearly with the growth of mean wind speed within the range of 0~20m/s. The estimation formula of the modal frequencies of high-rise buildings considering the influences of different wind speeds is put forward, which is expected to fill the gap in the existing specification for the quantitative analysis of the influences of wind-loads on the fundamental frequencies of high-rise buildings. [ABSTRACT FROM AUTHOR]

The present research aims to explore, by large-eddy simulation (LES), the potentiality and mechanism of multiple surface dielectric barrier discharge (multi-SDBD) plasma actuators to manipulate mean and fluctuating wind loads on a low-rise building. Three actuator configurations are located on the roof to induce directional wall jets in different directions. The effects of these configurations on flow structure and wind loads are studied in absence and presence of approaching flow. Results show that all subgrid-scale models can obtain accurate roof pressure, and for the diffusion and convection terms, the bounded central differencing scheme can provide more accurate predictions for the roof pressure. The control impact of active actuators gradually weakens with the increase of the approaching flow velocity. The direction of the wall jet can determine the position of the limited roof region with the reduced mean pressure coefficient. The multi-SDBD actuators continue to absorb the upstream flow and blow this flow downstream, meaning the wall jet exerts strong pressure on the local roof area at the end of the jet, which results in a significant reduction of the mean pressure coefficient. Furthermore, the counter-rotating vortices caused by the wall jet restrain the size and strength of the vortex shedding, thereby achieving the purpose of reducing the fluctuating pressure coefficient. Further analysis of the instantaneous vorticity fields indicates that the intensity and size of streamwise shedding vortices can be restrained by small-scale spanwise vortices induced by the plasma actuators. Under the action of the wall jet blowing from the trailing edge to the leading edge, the fluctuating lift and drag coefficients can be reduced by over 15% and the fluctuating pressure coefficient can be reduced by about 20% from the no actuation situation. [ABSTRACT FROM AUTHOR]