Published works

Large eddy simulation is performed for a flow through forest canopy applying various atmospheric stability conditions. The canopy is modelled as a horizontally homogenous region of aerodynamic drag with a leaf-area density (LAD) profile approximating the profile of a Scots pine tree. Varying atmospheric stability is incorporated into the simulation by applying varying heat flux in two different ways; (i) a surface heat flux prescription using Monin-Obukhov similarity functions and, (ii) a canopy heat flux model where heat from the canopy is modelled as distributed volume heat source. When the surface heat flux was prescribed, five stability classes: very unstable, unstable, neutral, stable and very stable are modelled while for canopy heat flux model three classes: stable, unstable and neutral are simulated for this study. We observe, realistically, that the stable and very stable velocity profiles are leaned towards right to neutral velocity profile indicating wind dominated flow. On the other hand, unstable and very unstable velocity profiles become more vertical indicating buoyancy dominated flow. In all velocity profiles, an inflection point is observed in the dense canopy region. Expected variations in the temperature profiles are also observed – higher near-ground temperature for unstable and very unstable cases and converse is true for stable and very stable cases. Simulations involving exponential heat source variation vertically for forest canopy is ongoing for validation with experimental data and other similar studies. Once validation is obtained, parametric study with various atmospheric stability can be carried out in order to improve operational models.