Air flow, temperature and humidity patterns in a greenhouse tunnel

Air distribution and climatic heterogeneity in greenhouses interfere with p lants activity and influence largely crop activity and more particularly tr anspiration and photosynthesis. This is particularly true for the tunnel, w hich is likely the most frequently used greenhouse type in the Mediterranea n basin, but which generates also a high climatic heterogeneity. Up to this time, most experimental studies of ventilation on full-scale greenhouses h ave used tracer gas techniques that allow neither clear identification of t he component of the total flux, nor predictions of the air flow pattern. Th is lack of experimental data and the complexity of the turbulent flows arou nd intricate boundary conditions explain why detailed air motion inside gre enhouse remain poorly known and seldom considered in greenhouse numerical s imulation. It is the reason why we characterised the mean air flows togethe r with air temperature and humidity patterns in a classical 8 m width "Filc lair" tunnel situated in the region of Avignon in the south of France. Usin g three- dimensional sonic anemometers and krypton hygrometers, the mean ai r speed, temperature and humidity were investigated in two vertical cross s ections of a tunnel. The spatial distribution of air flow is presented, tog ether with the associated temperature and humidity patterns. These results reveal a strong climatic heterogeneity in the tunnel.