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| Approximate analytical model for high-order power function of solute transport in soil |
| Wei Feng1,2, Wang Quanjiu1, Zhou Beibei1 |
| 1. Institute of Water Resource, Xi′an University of Technology, Xi′an, Shaanxi 710048, China; 2. School of Science, Xi′an University of Technology, Xi′an, Shaanxi 710048, China |
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Abstract To simulate the soil solute transport and estimate the transport parameters with a simple analytical model, an approximate six-power function model for describing the distribution of solute concentration was developed based on six-power function concentration profile assumed and the extended boundary layer theory describing the soil solute transport. The solute concentration profiles predicted by using the model proposed with different power indexes were compared and analyzed at two time instances(t=360, 720 min)and a long distance(120-450 cm). The simulated results showed that the solution of six-power function method is more close to the exact solution compared with other power models when the pore water velocity is 0.01 cm/min at a short time experienced(t=360 min)in a long traveling distance(x>50 cm). More computations indicated that the small pore water velocity(v≤0.01 cm/min)has little effect on the boundary layer distance. In that case, a series of error analysis on the transport parameters estimated with different boundary layer distance formulas were also carried out. The results indicated that the transport parameters such as diffusion coefficient and delay factor in the solute convection-dispersion equation can be decided precisely by using the boundary layer distance predicted with six-power function model based on measured results by means of instrument with higher sensitivity.
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Received: 12 October 2012
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