Comparative Analysis of the Air Flow in Different Cultures Inside a Greenhouse Using CFD

The air-flow dynamics in crops (cultures), when a crop is considered as porous media, is determined by factors depending of the phenological stage which define size and shape of the leaves. Leaves topology with respect to the wind direction determines the porosity of the media and in consequence the flow rate. This flow rate is a function of the porosity and permeability, which determines the dragging coefficient. The presence of crops in a greenhouse causes a consumption of momentum due to the resistance that the leaves offer for the friction force (drag forces). In this paper the greenhouse airflow dynamics is analyze for four different crops with different leaf configurations. Computational Fluid Dynamics (CFD) was used to model the airflow dynamic behavior considering a crop as porous media. The pressure reduction due to the effect of inertial force is represented by a Forcchaimer equation, which describe dragging forces (drag effect) depending on the crop density foliar area. The results indicate a reduction of 33 % in the wind speed along the cropped area; this causes a thermal gradient increase of 6 K in a length of 34 m.