Effects of free-stream turbulence on non-Gaussian characteristics of fluctuating wind pressures on a 5:1 rectangular cylinder

The statistical characteristics of fluctuating pressures on three 5:1 rectangular cylinder models with different scale ratios were measured in three turbulent flow fields, and the effects of turbulence parameters on the nonGaussian features of fluctuating pressures beneath the separating flow were investigated in detail. The fluctuating pressures beneath the separating flow exhibit pronounced non-Gaussian features with varying degrees along the chordwise direction, and these non-Gaussian behaviors to strongly depend upon the turbulence intensity; however, almost negligible influence of the ratio of integral scale to depth is observed. When only the integral scale-to-depth ratio changes, there are almost no variations in the corresponding statistical parameters, including skewness, kurtosis, spatial correlation, time history, and probability density distribution. In contrast, as the turbulence intensity increases, the above-mentioned statistical parameters vary significantly, and the nonGaussian features of fluctuating pressures become more evident. Furthermore, the values of the non-Gaussian peak factors of fluctuating pressures beneath the separating flow are significantly different because of varying degrees of non-Gaussian features, and increase significantly with the increase in the turbulence intensity. Hence, the effects of free-stream turbulence parameters, in particularly the turbulence intensity, should be accurately modeled in wind tunnel model tests to improve the prediction accuracy of design pressures on structures.

Automated summary

The study found that fluctuating pressures beneath the separating flow exhibit non-Gaussian features, strongly influenced by turbulence intensity. When the ratio of integral scale to depth changes, there is almost no variation in statistical parameters.