Modelling of two-dimensional infiltration experiments of water or diesel oil in an instrumented 2D channel

Abstract

This paper reports the modelling of two-dimensional infiltration experiments, with diesel or water as the permeate liquids in an unsaturated dune sand. Also reports the measurements of soil hydraulic properties (retention curve and saturated hydraulic conductivity) in laboratory, and infiltration experiments using a 2D channel. The time ratio (T_diesel/T_water) for the wetting fronts to reach the tensiometers was consistent with the ratio of mobilities water/diesel, $\left[\left({\rho }_{\omega }/{\mu }_{\omega }\right)/\left({\rho }_d/{\mu }_d\right)\right]=5.5.$ The SEEP/W, a numerical 2D code, modelled well the successive wetting front vertical positions for the liquids. However, the simulations for the lateral spreading were better for diesel, as this experiment was a complete wetting phenomenon, differently for water, that developed unsaturated conditions inside the column. The Philip 1D equation modelled the successive vertical positions for the liquids, using two different sets of parameters. The first set (ϕ, K_ñsat, h_p = 0): porosity, unsaturated hydraulic conductivity and incipient hydraulic head; and the second set, (ϕ_c, K_sat, h_p = 0): corrected porosity value to include the plume lateral spreading, saturated hydraulic conductivity and incipient hydraulic head. Although both sets of parameters are adequate to model the vertical component of the infiltration experiments, the first set is more efficient as it is independent of the corrected porosity, a value known afterwards.

Keywords:

• Numerical and analytical modelling
• two-dimensional infiltrations
• unsaturated sand
• infiltration of water or diesel
• instrumented 2D channel

Disclosure statement

No potential conflict of interest was reported by the authors.