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dc.contributor.authorPedretti, Daniele
dc.contributor.authorFiori, Aldo
dc.date.accessioned2013-10-09T08:26:06Z
dc.date.created2013-10
dc.date.issued2013-10
dc.identifier.citationPedretti, D.; Fiori, A. Travel time distributions under convergent radial flow in heterogeneous formations: Insight from the analytical solution of a stratified model. "Advances in water resources", Octubre 2013, vol. 60, p. 100-109.
dc.identifier.issn0309-1708
dc.identifier.urihttp://hdl.handle.net/2117/20342
dc.description.abstractWe analyze conservative solute transport under convergent flow to a well in perfectly stratified porous media, in which the hydraulic conductivity is treated as a random spatial function along the vertical direction (K(z)). The stratified model provides a rare exception of an exact analytical solution of travel time distributions in the proximity of pumping wells, and it is used here to obtain insights about ergodic and nonergodic transport conditions under nonuniform flow conditions. In addition, it provides a benchmark for numerical models aiming to correctly reproduce convergent flow transport in heterogeneous media, such as indicating the minimum number of layers required to obtain ergodic travel time distributions using only one model realization. The model provides important insights about the shape of the depth-integrated concentrations over time measured at the well (breakthrough curves, BTCs), which are usually applied to obtain transport parameters of the subsurface. It can be applied to any degree of system’s heterogeneity and using either resident or flux-weighted injection modes. It can be built using different probabilistic distributions of K. In our analysis, we consider a log-normal K distribution, and the results indicate that, especially for highly heterogeneous systems, described by the log-K variance (View the MathML source), the minimum number of layers required for from one model simulation to reproduce ergodic travel time distributions can be prohibitively high, e.g., above 106 for View the MathML source considering flux-weighted injections. This issue poses serious concerns for numerical applications aiming to simulate transport in the proximity of pumping wells. In addition, this simple solution confirms that stratification can lead BTCs to display strong preferential flow and persistent, power-law-like late-time tailing. Since the latter are common phenomenological macroscale evidences of other microscale hydrodynamic processes than pure advection (e.g., mass-transfer), caution must be taken when inferring aquifer properties controlling the anomalous transport dynamics in heterogeneous media from BTCs fitting.
dc.format.extent10 p.
dc.language.isoeng
dc.publisherElsevier
dc.subjectÀrees temàtiques de la UPC::Matemàtiques i estadística::Matemàtica aplicada a les ciències
dc.subjectÀrees temàtiques de la UPC::Enginyeria civil::Geologia::Hidrologia
dc.subject.lcshAquifer characterization
dc.subject.otherAquifer characterization Hydraulic heterogeneity Permeability Radial flow Stratified media Depth-integrated concentrations Exact analytical solutions Heterogeneous formation Numerical applications Probabilistic distribution Travel time distributions Aquifers Groundwater flow Mathematical techniques Mechanical permeability Porous materials Probability distributions Solute transport Travel time Well pumps Analytical models
dc.titleTravel time distributions under convergent radial flow in heterogeneous formations: Insight from the analytical solution of a stratified model
dc.typeArticle
dc.subject.lemacAqüífers -- Models matemàtics
dc.contributor.groupUniversitat Politècnica de Catalunya. GHS - Grup d'Hidrologia Subterrània
dc.identifier.doi10.1016/j.advwatres.2013.07.013
dc.description.peerreviewedPeer Reviewed
dc.rights.accessRestricted access - publisher's policy
local.identifier.drac12792109
dc.description.versionPostprint (published version)
dc.date.lift10000-01-01
local.citation.authorPedretti, D.; Fiori, A.
local.citation.publicationNameAdvances in water resources
local.citation.volume60
local.citation.startingPage100
local.citation.endingPage109


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