CFD study of external pressure coefficient over two greenhouses with parabolic roofs in tandem arrangement with numerical approximation

Greenhouses are usually constructed in high density and are located mainly in rural areas. The high density of greenhouses affects the local wind characteristics and subsequently the pressure coefficient distribution on the greenhouse frame, which is usually constructed by steel. The external pressure coefficient (c_p) is used for the design and construction of the metal frame in order to ensure the static integrity of the structure against the wind load. The EC1 in conjunction with EN 13031-1:2001, which is specialized for greenhouses, gives values for this coefficient. However, when two structures are situated very close to each other the Eurocode do not provide values for the pressure coefficients on them, which is a common situation in greenhouse areas. The present work studied the external pressure coefficient over two greenhouses with parabolic roofs in tandem arrangement. A CFD approximation was suggested to simulate the incompressible, two-dimensional, steady and viscous airflow around the structures. The numerical results, as contours of pressure (isobars) and coefficients of pressure, were compared qualitatively and quantitatively with available data from the EN 13031-1:2001 for a single structure. The results of this study will be useful for agricultural engineers in the design of greenhouses.