Effects of turbulence intensity and scale on surface pressure fluctuations on the roof of a low-rise building in the atmospheric boundary layer

The effects of turbulence scales on the surface pressure fluctuations near the roof edge were investigated using the IBHS Research Center's full-scale wind tunnel under four sets of flow conditions on a full-scale replica of the TTU-WERFL building. These flow conditions ranged from streamwise turbulence intensities of 4%–16%, with varied spectral content. It was found that it is the energy levels of the streamwise velocity fluctuations over the range of non-dimensional frequencies, 0.1 < fH/V < 2, which are active, controlling both the magnitude and distribution of the surface pressure fluctuations near the roof edge of low-rise buildings in the atmospheric boundary layer. The data indicate that, for the relatively high levels of turbulence energy typical of the atmospheric surface layer, there are (i) significantly smaller mean reattachment lengths, with (ii) much higher peak and fluctuating pressures, which are (iii) located closer to the roof edge. This range wavenumbers is one to two orders of magnitude larger in size than those associated with the width of the separated shear layer and Melbourne's small-scale turbulence parameter. This implies that partial turbulence simulation methods must capture the energy at these scales in order to lead to accurate wind tunnel simulations of low-rise building aerodynamics.