Reference Static Pressure Effect on Fluctuating Wind Pressure on Roofs of Low-Rise Buildings in Open-Circuit Wind Tunnels

The structural characteristics of open-circuit wind tunnels result in internal static pressure instability, which can affect the accuracy of wind pressure coefficient measurements on rigid models of low-rise buildings. To address this issue, a Pitot tube and an ESP electronic pressure scanning system were used to collect data on reference static pressure variation and wind pressure on the roof of a low-rise building under Class B wind terrain and different temperature conditions. The results indicate that the reference static pressure decreases with increasing temperature and is significantly influenced by external airflow disturbances at the beginning of the experiment, and it tends to stabilize approximately 5 min after the wind tunnel is activated. The probability density of reference static pressure under different conditions mostly follows a Gaussian distribution, although a few samples exhibit heavy-tailed or skewed fluctuations. The sliding standard deviation and coefficient of variation of the reference static pressure are both relatively small, but occasional samples show extreme fluctuations. It is recommended to apply filtering techniques or repeated measurements to reduce experimental errors. At a wind direction angle of 0°, the fluctuating wind pressure coefficients on the roof calculated using reference static pressures from different samples exhibit good consistency. The average mean relative error of the fluctuating wind pressure coefficients across roof zones I–VIII was 3.71%, which is within an acceptable range. The research findings provide a useful reference for reducing result errors in wind pressure tests conducted in open-circuit wind tunnels.