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Modelling the relation between turbulence scales in atmospheric wind and surface pressures on low-rise buildings is important for prediction of wind loads on structures. Because the interest is in events that take place over short time periods, wavelet analysis is performed to characterize this relation. The Morlet wavelet transform is applied to simultaneously measured velocity components of atmospheric wind and surface pressures at multiple locations on a low-rise building. The wavelet energy density of the individual time series show that both atmospheric turbulence and pressure fluctuations are highly intermittent, i.e. the energy of the different scales in these fluctuations varies significantly with time. Furthermore, the low-pressure peaks are represented by high levels of the wavelet energy density. Cross-scalogram results show that there is a clear relationship between energetic events in the atmospheric wind and low-pressure peaks that occur simultaneously at pressure taps placed over a large area of the low-rise building. Specifically, there is a scale relation between theu- andv-velocity components of the incident wind and the pressure fluctuations. Such results show that better prediction of pressure peaks can be obtained by simulating turbulence events rather than merely matching integral length scales, mean flow parameters or turbulence intensity. |
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