Numerical and analytical modelling of advective travel times in realistic three-dimensional fracture networks
2011 (English)In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 47, no W02506, 16pp- p.Article in journal (Refereed) Published
Travel time distributions obtained from advective transport in multiple realisations of realistic discrete fracture network simulations are analysed using the truncated one-sided stable distribution, which has previously been shown to generalise both the advection-dispersion solution as well as one-sided stable distributions. Using this model it is shown that the Fickian assumption inherent in the advection-dispersion equation generally fails, despite that the first two moments of travel time essentially scale linearly with distance. It is also observed that the equally probable realisations drawn from the ensemble can produce a wide range of behaviour under the current configuration, such that Fickian conditions are almost obtained in some cases for increasing scales. Based on a small-scale calibration against particle breakthrough, the model is then shown to successfully predict limiting bounds of transport for a one order of magnitude increase in scale. Correlation in particle velocity is explicitly shown to be significant for scales close to the characteristic Lagrangian segment length. The network configuration is obtained from extensive site characterisation data at the Laxemar region in Sweden, and represents a block scale domain of reasonably sparse background fractures.
Place, publisher, year, edition, pages
2011. Vol. 47, no W02506, 16pp- p.
Fractured media; Transport; Advection; Fickian dispersion; One-sided stable densities; Stochastic simulation
Earth and Related Environmental Sciences Oceanography, Hydrology, Water Resources Other Environmental Engineering
IdentifiersURN: urn:nbn:se:kth:diva-11972DOI: 10.1029/2010WR009290ISI: 000287039900001ScopusID: 2-s2.0-79851496854OAI: oai:DiVA.org:kth-11972DiVA: diva2:291684
QC 20110209. Uppdaterad från "accepted" till "published"(20110209).2010-02-022010-02-022011-03-25Bibliographically approved