CFD coupled modeling of distributed plant activity and climate in greenhouse

Abstract

For the 1990’s Computational Fluid Dynamics (CFD) has allowed significant progresses for modeling the greenhouse distributed climate, including at crop level. It chiefly relies on the dynamic action of the crop on air flow and the subsequent heat and mass exchanges.
Thus, the CFD approach combined different scales of modeling: the greenhouse and its environment together with crop canopy with a precision of a couple of cm3, corresponding to the current dimension of the average finite volume meshes inside the greenhouse. This modeling approach accounts for the coupling of air transfers within the crop that is assimilated to the solid matrix of a porous medium exchanging heat and mass with air. Thus, the source terms for sensible and latent heats and other mass exchanges are assigned to each cell of the porous medium (i.e. canopy). These source terms are encapsulated in so call “User Defined Function’s” (UDFs) dynamically linked with the CFD solver. Temperature, air humidity and CO2 distributions within the crop canopy can then be deduced from the local air velocity and the distributed climate parameters together with canopy temperature and activity.