Modelling airflow within model plant canopies using an integrated approach

A direct 3D CFD modelling of airflow within model plant canopies was performed with separate models for the leaves and the branches of the canopy. The effect of the branches on airflow was modelled by introducing the 3D architecture of the canopies into the model and that of the leaves was modelled by adding drag force terms in the momentum and turbulent energy equations in porous sub-domains created around the branches. Wind tunnel experiments were used to validate the model. The experiments were carried out for inlet velocities of 10 m s−1 and 15 m s−1 with two artificial 1:10 scaled model trees, fully leafed, half leafed and leafless. Simulations were made with a full closure model (FCM) and with the presented integrated model (IM). FCM and IM gave a maximum percent error of 34 and 30, respectively for average air velocity, U. On horizontal average basis both methods gave fairly comparable accuracies with maximum errors of 16.6% for FCM and 13.7% for IM but on local basis both horizontally and vertically within the tree height the present approach gave a better accuracy. The present model also gave qualitatively good results for turbulent kinetic energy.