Effects of the Turbulence Integral Scale on the Non-Gaussian Properties and Extreme Wind Loads of Surface Pressure on a CAARC Model

Abstract

To study the effects of the turbulence integral scale on the non-Gaussian properties and extreme wind loads of surface pressure, the surface pressures for two Commonwealth Advisory Aeronautical Research Council (CAARC) scaled models were measured in three turbulent flow fields with different turbulence integral scales. The results show that the surface pressure distribution on the windward surface is fundamentally Gaussian, while the surface pressures on the side and leeward surfaces are markedly non-Gaussian. The deviation from normality strongly depends on the ratio of the turbulence integral scale to the windward width (Lux/D). With changing Lux/D, the fluctuating pressure, skewness, kurtosis, probability density distribution, non-Gaussian peak factors, and extreme wind loads vary significantly. In addition, the surface pressure nonnormality becomes more evident for lower Lux/D wind fields, increasing Sk, Ku, and the fluctuating pressure’s peak factor. In contrast, the fluctuating pressure decreases with decreasing wind-field Lux/D, resulting in the underestimation of extreme wind loads. Further, the extreme wind load maximal error margin reaches 30.7% when the simulated turbulence integral scale error margin is 70%, even for nonnormal surface pressures. Hence, nonnormality of the surface pressure and the effects of the turbulence integral scale should be carefully considered when estimating extreme wind loads for CAARC standard tall buildings using wind-tunnel tests.