Publications des scientifiques de l'IRD

Fahs M., Ataie-Ashtiani B., Younes Anis, Simmons C. T., Ackerer P. (2016). The Henry problem : new semianalytical solution for velocity-dependent dispersion. Water Resources Research, 52 (9), p. 7382-7407. ISSN 0043-1397.

Titre du document
The Henry problem : new semianalytical solution for velocity-dependent dispersion
Année de publication
2016
Type de document
Article référencé dans le Web of Science WOS:000386977900038
Auteurs
Fahs M., Ataie-Ashtiani B., Younes Anis, Simmons C. T., Ackerer P.
Source
Water Resources Research, 2016, 52 (9), p. 7382-7407 ISSN 0043-1397
A new semianalytical solution is developed for the velocity-dependent dispersion Henry problem using the Fourier-Galerkin method (FG). The integral arising from the velocity-dependent dispersion term is evaluated numerically using an accurate technique based on an adaptive scheme. Numerical integration and nonlinear dependence of the dispersion on the velocity render the semianalytical solution impractical. To alleviate this issue and to obtain the solution at affordable computational cost, a robust implementation for solving the nonlinear system arising from the FG method is developed. It allows for reducing the number of attempts of the iterative procedure and the computational cost by iteration. The accuracy of the semianalytical solution is assessed in terms of the truncation orders of the Fourier series. An appropriate algorithm based on the sensitivity of the solution to the number of Fourier modes is used to obtain the required truncation levels. The resulting Fourier series are used to analytically evaluate the position of the principal isochlors and metrics characterizing the saltwater wedge. They are also used to calculate longitudinal and transverse dispersive fluxes and to provide physical insight into the dispersion mechanisms within the mixing zone. The developed semianalytical solutions are compared against numerical solutions obtained using an in house code based on variant techniques for both space and time discretization. The comparison provides better confidence on the accuracy of both numerical and semianalytical results. It shows that the new solutions are highly sensitive to the approximation techniques used in the numerical code which highlights their benefits for code benchmarking.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020] ; Hydrologie [062] ; Géologie et formations superficielles [064]
Localisation
Fonds IRD [F B010068323]
Identifiant IRD
fdi:010068323
Contact