Teitel, M., Institute of Agricultural Engineering, Agricultural Research Organization, Volcani Center, P.O.B. 6, Bet Dagan, 50250, Israel
Wenger, E., Institute of Agricultural Engineering, Agricultural Research Organization, Volcani Center, P.O.B. 6, Bet Dagan, 50250, Israel

Screens are widely used in agriculture for various purposes. For instance, insect proof screens are used for insect exclusion; thermal screens, made of highly reflective low-emissivity materials, are used to reduce thermal radiation losses; shading screens are used for heat load reduction and coloured screens are used to filter out different colours in the visible spectrum. In all cases, the screens form an enclosed space (screenhouse) in which the plants are grown in a modified climate. The screens generally alter the airflow within the enclosure in comparison to flow in an open field and thus affect air velocity near the plant organs and hence other significant parameters such as leaf and canopy resistances to H2O and CO2 transfer. Two dimensional CFD simulations are carried out to determine the effect of screenhouse roof shape on the flow around and within the enclosure. The study mainly concentrates on the comparison between the airflow patterns and air velocities with flat and different pitched roofs.