Numeric modeling to simulate the soil water evaporation process
01/Oct/2005
Several laboratory tests were carried out with the objective of evaluating the performance of a numerical model to simulate the unidimensional soil water evaporation process. This model was created based on Richard’s equation linearized in space and by an iterative Newton-Raphson method to solve this unlinearized equation in time. The model considers the vapor flow within the soil profile and its evaporation rate on the surface. Results showed that the model simulated the soil water evaporation process satisfactorily for both […]
Analytical models to estimate the soil water redistribution process
01/Oct/2003
Field assessments of the water redistribution process are time consuming and costly because hydraulic soil properties vary extensively in space and time. The present work proposes two analytical models to estimate the dynamics of this process, based on the use of the hydraulic unit potential gradient of Richard’s equation. The first model estimates the soil water content and the second flow density, both as functions of time for internal drainage at a given depth. From statistical and physical points of […]
Parameter variability of the equation relating hydraulic conductivity to soil water content using the instantaneous profile method
01/Dec/1999
Hydraulic conductivity is one of the most important soil properties for studies dealing with infiltration, water movement within the soil profile and to plant roots and internal drainage. The availability of the function hydraulic conductivity x soil water content (K(θ)) is essential to these studies. However, little is known about the variability of the empirical parameters of this function. Aiming to contribute with information on the variability of these parameters, a study is described in which observations of hydraulic conductivity […]
Experimental evaluation of a numerical model for a soil-water redistribution process
01/Jun/1999
To test the performance of a numeric model in prediction of water content (θ) and tension (|ψm|) in time and space, data were chosen from the literature on two porous materials with different hydraulic properties: a marine sand (quatzipsamment) of Tottori, Japan and a sandy phase Red-Yellow Latosol (Haplustox) of Piracicaba, SP. The results led to the following conclusions: (a) in both porous materials studied, the behaviour of the model was highly significant, with the profiles of humidity aligning satisfactorily […]