Wind tunnel simulation of time variations of turbulence and effects on pressure on surface-mounted prisms

Roughness elements are usually added in boundary layer wind tunnels to enhance the energy of certain turbulence scales and their range. In this work, flow characteristics in three different configurations of roughness elements are examined. Orthonormal wavelets are applied to velocity records in order to quantify the percentage of energy contribution of each scale to the total energy and the intermittency of high-energy events. The effects of such variations in turbulence scale characteristics on variations of peak and mean negative pressure coefficients at different locations on a 1:50 scale model of the Wind Engineering Research Field Laboratory (WERFL) of Texas Tech are also determined. The results show that enhancing the energy of the smaller turbulence scales relative to that of the larger scales and in particular the energy of the intermittent events have significant effects on mean and peak pressures observed on the top surface of a prism.