Results 211 to 220 of about 7,999 (257)

Scheduling Irrigation From Wetting Front Depth

Agricultural Water Management, 2017
Abstract Irrigation scheduling is often based around the analogy of a ‘tipping bucket’, and the measurement or prediction of the amount of water stored within the bucket. We compare this conventional approach of scheduling with stopping irrigation when the bucket tips i.e. when infiltrating water moves from an upper to a lower soil layer.
John G Annandale
exaly   +2 more sources

Comment on “Dynamics of wetting fronts in porous media”

Physical Review E, 2000
A new method to model unsaturated flow in porous media was presented in Phys. Rev. E 58, R5245 (1998). We analyze the proposed approach and illustrate some significant shortcomings.
W G, Gray, C T, Miller
openaire   +2 more sources

Description of the wetting front

International Journal of Heat and Mass Transfer, 1984
Etablissement d'une formule approchee representant le front de mouillage d'un milieu ...
openaire   +1 more source

Stages in the adoption of a wetting front detector

Irrigation and Drainage, 2009
AbstractThe adoption of a new irrigation scheduling tool by irrigators in South Africa was evaluated while it was still in prototype form. A wetting front detector (WFD) is a funnel‐shaped device, buried in the crop root zone, which provides a mechanical or electronic signal to the irrigator when a wetting front moves past it.
R. J. Stirzaker, J. B. Stevens, J. G. Annandale, J. M. Steyn   +3 more
openaire   +1 more source

A WETTING FRONT ARRIVAL TIME PROBE

Transactions of the ASAE, 1990
ABSTRACT A research tool has been developed to shed light on the relationship of soil compaction to irrigation infiltration wetting front arrival time in the field. A tractor-mounted, hydraulic-powered, probe insertion package forces a tapered stainless steel probe with an ASAE standard large cone penetrometer tip into the ground. In place, the tapered
null D. L. Baker, null P. D. Ayers
openaire   +1 more source

Two-Dimensional Infiltration and Wetting Fronts

Journal of the Irrigation and Drainage Division, 1965
To study two-dimensional infiltration, fourteen field tests on four different soils were made. During the tests, the advance of the wet front was followed visually. The tests show that both vertical and lateral advances of the wet front fit theoretical equations. An empirical equation is found that relates cumulative infiltration to time. The tests are
Sdkik Toksoz, Don Kirkham, E. Robert Baumann   +2 more
openaire   +1 more source

Wetting Front Instability in Layered Soils

Soil Science Society of America Journal, 1972
Abstract Percolation of a one‐dimensional wetting front in homogeneous soil is known to be stable. On the other hand, in a layered soil whose upper layer is finer and less conductive than the coarser layer beneath, the wetting front becomes unstable and breaks into narrow wetting columns, or “fingers,” in which flow is three ...
D. E. Hill, J.‐Y. Parlange
openaire   +1 more source

Wetting Front Analysis of the Richards’ Equation with Impervious Boundary

International Journal of Nonlinear Sciences and Numerical Simulation, 2018
Abstract It is analyzed the wetting front of the Richards’ equation (RE) for horizontal infiltration problem with impervious layer in a finite medium, and obtained an approximate analytical solution by the series expansion technique. The present approximation is suitable for arbitrary diffusivity in RE and applied to simulate the changes
Chen, Xi, Dai, Ying
openaire   +1 more source

Roughness of wetting fluid invasion fronts in porous media

Physical Review Letters, 1992
We report an imbibition experiment that involves water displacing air in a Hele-Shaw cell filled with glass beads. We varied the flow rate such that the capillary number (${\mathit{C}}_{\mathit{a}}$) spans the range ${10}^{\mathrm{\ensuremath{-}}5}$${\mathit{C}}_{\mathit{a}}$${10}^{\mathrm{\ensuremath{-}}2}$.
, He, , Kahanda, , Wong
openaire   +2 more sources

A Capillary Microstructure of the Wetting Front

Transport in Porous Media, 1998
This article reports the experimental results of a study of the wetting-front microscale structure formed only by capillary forces in homogeneous and random etched glass capillary models. In the homogeneous model, water propagates through the capillary system, evenly filling the capillaries across the direction of flow.
openaire   +1 more source