Aflexible model to characterize soil con tamination: adaptation of the normal distribu tion of hydrodynamic dispersion to different cases of hydric miscible displacement
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| Autor: | |
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| Formato: | artículo original |
| Estado: | Versión publicada |
| Fecha de Publicación: | 2004 |
| Descripción: | The analytical model of normal equitable distribution of micro velocities (compared to the velocity of the plane, p=1, of piston flow) for hydrodynamic dispersion has been adapted to also handle cases of biased distribution in solute transport in one dimensional soil moisture flow. The selected version of the equation includes two constants dimensionless: Pe the Peclet number, and R, the solution-soil interaction factor. The effluent break through curve for a continuous pulse of solution with concentration c0, which displaces a soil column saturated with distilled water, is expressed as follows: p is the number of pore volumes displaced, with the volume defined by the plane of sampling of the effluent, whose concentration is c; z is the number of standard deviations. The equitable distribution model has been explained by using data from an experimental case. The equation contains the standard integral of the normal curve, which is found in the Microsoft Excel list of functions and this facilitates a rapid spreadsheet calculation (pro gram included) and visual inspection to deter mine Pe from experimental data. R is the value of p when c/c0=0.5. The reference plane, p=1, of pis ton flow is conserved. Therefore, when R<1 or >1, a biased distribution occurs. R=1, when there is no solution-soil interaction and the distribution is equi table. The degree of association r2 (program includ ed), was tested between the calculated (fitted) and experimental values of c/c0 for selected values of p for a variety of soils: a Ben Lomond sand with Pe=203.4, R=1, and r2=0.99; an Aiken clay loam (red soil,1-2 mm aggregates), Pe=9, R=0.92, and r2=0.99, both soils from California, EE.UU.; a clayey Oxic Dystropept, La Selva, Costa Rica, very aggregated, Pe=0.4 (shows preferential flows), R=0.11, and r2=0.88; a Hapludult with 48% clay and 32% silt, Pe=9, R=2 and r2=0.99, Guadalupe, Perez Zeledón, Costa Rica, and a dark red Latosol, Petrolina, Brazil, Pe=15, R=2.9 and r2=0.99. |
| País: | Portal de Revistas UCR |
| Institución: | Universidad de Costa Rica |
| Repositorio: | Portal de Revistas UCR |
| Lenguaje: | Español |
| OAI Identifier: | oai:portal.ucr.ac.cr:article/61226 |
| Acceso en línea: | https://revistas.ucr.ac.cr/index.php/agrocost/article/view/61226 |
| Palabra clave: | Tropical soils biased dispersion hydric contamination miscible displacement model Suelos tropicales dispersión sesgada contaminación hídrica modelo de desplazamiento miscible |