## 2 Experimental Methodology
### Experimental Procedure  
In addition to the velocity measurements, the surface pressure has also been obtained at different locations to present a comprehensive database where pressure and wind speed results can be used as a validation test case. The surface pressure on the roofs of the models was measured using 64 pressure taps, distributed as shown in Figure 4. The pressure sensors are four active element piezoresistive bridges. Two different pressures sensors were used: Honeywell 170 PC (measurement range: \(\pm\)35 mbar) and AMSYS 5812-0001-D-B (measurement range: \(\pm\)10.34 mbar). Due to the narrow spaces in the model, the pressure sensors were placed outside of the model and connected to the bores in the wooden deck by brass connectors (inner diameter 1 mm) and plastic pressure tubes (inner diameter 1.5 mm), that are freed from burrs and debris. The length of plastic pressure tubes was about 0.9 m. The calibration of the pressure measurement system included two phases: static and dynamic. The static calibration was performed to establish the pressure-voltage relation for each pressure sensor, while dynamic calibration was performed to correct the dynamic effects of tubes [53]. Surface pressures were acquired with a sampling frequency of 1000 Hz and were scanned in a sample-and-hold modus, enabling the simultaneous sampling of signals. For each measurement, 28 samples of 4.7 s length were collected, where each sample corresponds to a 10 min long sample in full scale. The maximum uncertainty of surface pressures based on five repeated measurements was estimated to be \(\sim\)2.5%. More details about the pressure measurement equipment that consisted of pressure sensors, a tubing system, amplifiers and analog/digital (A/D) converters can be found in [54]. The velocities above the roof were mainly measured at three different heights (z/\(D\) = 0.075, 0.3 and 0.45) above the points marked in red in Figure 4. In addition, above points 36 of the flat roof and 58 of the deck roof, at the centre of the roof, ten heights are considered with the spacing of z/\(D\) = 0.075. The hot-wire anemometer consisted of two cross wires allowing to measure both stream-wise and vertical velocity components. All velocity data, including hot-wire anemometer and Prandtl tube, are sampled with the frequency of 2000 Hz. The hot-wire anemometer was calibrated in laminar flow conditions in a calibration tunnel by exposing a probe to the set of known velocities, while corresponding voltages were recorded. The adopted fitting curve is a fourth order polynomial curve with coefficients calculated by fitting the data in the least-squares sense. Uncertainties related to the velocity measurements were calculated following the procedure presented by [55; 56]. The total uncertainty of the velocity consisted of calibration, linearisation, positioning of the probe, digitalisation and uncertainty due to variation in the experimental conditions (such as temperature or  
Figure 4: Distribution of pressure taps on the surface of the high-rise buildings: (**a**) at the flat roof and (**b**) at the deck roof, for 0\({}^{\circ}\), 15\({}^{\circ}\), 30\({}^{\circ}\) and 45\({}^{\circ}\) wind angles. ambient pressure). The maximum uncertainty of the time-averaged stream-wise velocity was 5.6%. The maximum uncertainties of the stream-wise and vertical turbulence intensities were estimated to be 9.6% and 9.4%, respectively. These uncertainty estimates correspond to the 95% confidence interval. The manual positioning of the hot-wire anemometer was detected as one of the main contributions to uncertainty, as established based on three repeated measurements at ten different heights above the middle point of the flat roof. The flow in the roof region is expectably inherently 3D. Some degree of cross-flow is expected in those regions of the flow where vorticity occurs, i.e., closer to the surface. Eventual three-dimensionality in the flow is estimated looking at the performance of the signal measurements and the level of turbulence intensity.