The influence of a parapet on local pressure fluctuations

Abstract Probability distributions of wind pressure coefficients have been measured on flat roofs of prismatic bodies in a simulated turbulent boundary layer in a wind tunnel. A κth-order Weibull distribution gives good agreement with the experimental data; the extreme-value distribution is of type I. The parameters of this extreme-value distribution can be calculated from the parameters of the initial distribution. For points behind a parapet the distribution functions are remarkably changed. For most of the points experiencing high suction, the reduction of the mean value of the pressure coefficient caused by the presence of a parapet is approximately the same as the reduction of the extreme-value coefficient.