DEPENDENCE ON STOMATAL RESISTANCE MODEL OF CFD SIMULATION OF CROP EVAPOTRANSPIRATION IN GREENHOUSES

In CFD codes, transport equations for airflow, heat and water vapour are solved throughout the domain of interest that consists, for greenhouse climate simulations, of the outside ambient air, the inside air and the crop.
For the first and the second parts, there are no major difficulties to model and solve these equations, on the other hand the particular composition of the crop leads to the choice of a specific model.
The crop is considered as a virtual homogeneous porous medium with well defined boundaries (parallelepiped) corresponding to the geometry of the crop stands.
Source or sink terms are defined for both the momentum equation (drag coefficient) and for heat and water vapour transfers in the leaf boundary layer.
These transfers depend on both the aerodynamic conditions in the crop cover and on the stomatal resistance of leaves.
Relation for the determination of the stomatal resistance based on the Jarvis model has been used involving a single parameter, the global radiation density at each node of the mesh of this virtual porous medium and the minimal stomatal resistance that depends on the crop’s leaves type, age together with their vertical location.
Empiric values issued from plant ecophysiology models have been chosen for this parameter.
In this paper, we analyze the consequence of the choice of the minimal stomatal resistance value on the simulation of the distribution of the climate parameters in the crop and in the greenhouse.
Results highlight the great sensitivity of this choice on the climate parameters distribution and consequently the necessity of an accurate determination of the stomatal resistance model.

International Symposium on High Technology for Greenhouse Systems: GreenSys2009

J.C. Roy, T. Boulard, R. Nebbali

greenhouse climate modeling, stomatal resistance

https://doi.org/10.17660/ActaHortic.2011.893.66