Estimate of the Terms of Turbulent Kinetic Energy Budget Equation in a Stratified Flow in Wind Tunnel Experiments

In the present work, experiments were conducted in a wind tunnel above a cooled surface with the aim of determining the influence of the thermal stratification on turbulence-related quantities. The experimental apparatus consists of an aluminum plate inserted at the bottom surface of the test section, which is then cooled until 5°C, so that a stably stratified surface is formed. As wind speeds increase, such a stable layer is soon destroyed. Data show that quantities such as temperature, variances, dissipation rates and turbulent fluxes are substantially reduced when a stratification is present. On the other hand, third and fourth order statistical moments, as well as the mean wind speed are very slightly affected by the stratification.