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Advective Transport Phenomena to Better Understand Dispersion in Field and Modeling Practice
The absence of recent research on dispersion in engineering applications indicates the need for a description that is more focused on field and modeling practice. Engineers may benefit from simple calculation tools allowing them to understand the processes encountered in the field. Based on a concep...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Blackwell Publishing Ltd
2019
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7004079/ https://www.ncbi.nlm.nih.gov/pubmed/30891733 http://dx.doi.org/10.1111/gwat.12883 |
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author | de Lange, Willem J. |
author_facet | de Lange, Willem J. |
author_sort | de Lange, Willem J. |
collection | PubMed |
description | The absence of recent research on dispersion in engineering applications indicates the need for a description that is more focused on field and modeling practice. Engineers may benefit from simple calculation tools allowing them to understand the processes encountered in the field. Based on a conceptual model for advective transport through an elongated conductivity zone, for example, in fluvial sediments, explicit expressions are presented for macro‐scale phenomena: (1) the different travel distances of water particles traveling in laminar flow through and adjacent to a single zone with conductivity higher or lower than that of the aquifer; (2) the affected thickness of the bundle of flowlines; (3) the distinction of inflow, outflow, and through‐flow sections; (4) the development of a plume front vs. that of a tail; (5) conservation of mass causing water particles to travel both slower and faster than the aquifer average velocity while passing a single zone. The spread derived from a spatial distribution in a field experiment relates to the geometric mean of the spreads of the plume front and tail. The results obtained for a single conductivity zone are expanded for a general aquifer that is characterized by stochastic parameters. A fundamental new expression describes the dispersive mass flux as the product of the advective volume shift and the related local concentration difference. Contrary to Fickian theory, the dispersive mass flux in both the front and tail of a plume in highly heterogeneous aquifers is limited. In modeling, the advective volume shift is proportional to the cell size. |
format | Online Article Text |
id | pubmed-7004079 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | Blackwell Publishing Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-70040792020-02-11 Advective Transport Phenomena to Better Understand Dispersion in Field and Modeling Practice de Lange, Willem J. Ground Water Research Papers/ The absence of recent research on dispersion in engineering applications indicates the need for a description that is more focused on field and modeling practice. Engineers may benefit from simple calculation tools allowing them to understand the processes encountered in the field. Based on a conceptual model for advective transport through an elongated conductivity zone, for example, in fluvial sediments, explicit expressions are presented for macro‐scale phenomena: (1) the different travel distances of water particles traveling in laminar flow through and adjacent to a single zone with conductivity higher or lower than that of the aquifer; (2) the affected thickness of the bundle of flowlines; (3) the distinction of inflow, outflow, and through‐flow sections; (4) the development of a plume front vs. that of a tail; (5) conservation of mass causing water particles to travel both slower and faster than the aquifer average velocity while passing a single zone. The spread derived from a spatial distribution in a field experiment relates to the geometric mean of the spreads of the plume front and tail. The results obtained for a single conductivity zone are expanded for a general aquifer that is characterized by stochastic parameters. A fundamental new expression describes the dispersive mass flux as the product of the advective volume shift and the related local concentration difference. Contrary to Fickian theory, the dispersive mass flux in both the front and tail of a plume in highly heterogeneous aquifers is limited. In modeling, the advective volume shift is proportional to the cell size. Blackwell Publishing Ltd 2019-04-15 2020 /pmc/articles/PMC7004079/ /pubmed/30891733 http://dx.doi.org/10.1111/gwat.12883 Text en © 2019 The Author. Groundwater published by Wiley Periodicals, Inc. on behalf of National Ground Water Association. This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc-nd/4.0/ License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made. |
spellingShingle | Research Papers/ de Lange, Willem J. Advective Transport Phenomena to Better Understand Dispersion in Field and Modeling Practice |
title | Advective Transport Phenomena to Better Understand Dispersion in Field and Modeling Practice |
title_full | Advective Transport Phenomena to Better Understand Dispersion in Field and Modeling Practice |
title_fullStr | Advective Transport Phenomena to Better Understand Dispersion in Field and Modeling Practice |
title_full_unstemmed | Advective Transport Phenomena to Better Understand Dispersion in Field and Modeling Practice |
title_short | Advective Transport Phenomena to Better Understand Dispersion in Field and Modeling Practice |
title_sort | advective transport phenomena to better understand dispersion in field and modeling practice |
topic | Research Papers/ |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7004079/ https://www.ncbi.nlm.nih.gov/pubmed/30891733 http://dx.doi.org/10.1111/gwat.12883 |
work_keys_str_mv | AT delangewillemj advectivetransportphenomenatobetterunderstanddispersioninfieldandmodelingpractice |