New Boundary Conditions for Positive and Negative Skewed Turbulence in Fluctuating Plume Models

An analytical function is found and is used as boundary condition for the barycentre trajectories in a fluctuating plume model. The skewness profile in the fluctuating plume model is accounted for at two levels: in the reflections at the boundaries and in the concentration PDF relative to the centroid position. The model is tested in convective (positively skewed) and canopy (negatively skewed) turbulence. The mean and fluctuations of the concentration field in canopy turbulence are compared to experimental data showing the important improvements determined by the inclusion of the skewness effects close to the ground.