SIMULATION OF WATER MOVEMENT IN ROCKWOOL SLABS USED AS GROWING MEDIA

Determination of the dynamics of water and nutrients in substrates is important because it allows for adjustment of the nutrient and water supply to plant needs during successive crop cycles. In this study, we focus on the movement of water in rockwool slabs used as growing substrates. Utilising the transport equation, root absorption is described by an experimentally determined sink term. Commercial Computer Fluid Dynamics (CFD) software was used to solve numerically in two-dimensions the equations of water movement. However, as the Richard’s equation describing the water movements in the substrate is quite different from the Navier Stokes equations used by the CFD, significant modifications of the standard transport equations were required. The numerical results were compared with experimental results and a sensitivity analysis was performed with respect to various physical parameters of the substrate. Based on this study, an alternative substrate design better adapted to closed systems was proposed.