Convective and ventilation transfers in greenhouses, part 2: Determination of the distributed greenhouse climate

Abstract

In this paper, the characterisation and modelling of the most relevant convective transfers contributing to the description of the distributed greenhouse climate are studied in detail. After a brief review of the equations governing flows within the greenhouse, the major theoretical approaches are recalled. The focus is on the study of the distributed climate which requires the equations governing the fluid flow and includes the turbulent transfer. The digitisation of these equations and their solution using computer fluid dynamics (CFD) software are presented. The measurement techniques associated with this approach are also presented, with special attention paid to the determination of air flows and climate patterns using advanced flow measurement techniques such as particle imagery visualisation (PIV) and sonic anemometry. A complete panorama of the studies pertaining to air movement inside the various greenhouse types is presented and it is particularly focused on recent studies dealing with plant-air interactions, particularly the leaf boundary layer climate and the air flows within the crop canopy. Despite the difficulties of modelling turbulent transfers, it is shown that simulations involving CFD software are becoming more realistic and able to describe with good accuracy the main features of the distributed climate inside the greenhouse. The major consequences of this progress are discussed with respect to improvement of the greenhouse climate through better plant protection and enhancements of greenhouse design and control. (C) 2002 Silsoe Research Institute. Published by Elsevier Science Ltd. All rights reserved.