Characteristic time scales of velocity and pressure events

Numerical and wind tunnel simulations of full-scale wind loads on structures are usually performed at a lower Reynolds number and different turbulence parameters. One way to assess the validity of such simulations is through matching magnitudes, duration and/or spectral characteristics of simulated pressure peaks with full-scale data. Because wavelet analysis provides a time/frequency decomposition, it has been proposed as an analysis tool for the intermittent and transient pressure peaks. This work aims at answering the question as to whether different wavelets yield the same-scale decomposition of pressure peaks and velocity events and could, thus, be used as a tool for the analysis of extreme loads on structures. The results show that, by isolating the peaks or events with a modified Gaussian window prior to applying the wavelet transform, the dependence of the measured time scale on different wavelet functions is reduced. The time scales of the pressure peak and the velocity event are estimated to be about the same indicating that one contributing factor, at the peak scale, to the pressure peak lies in the variation of the incoming flow at the same scale.