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| rdf:type
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| Description
| - Temporal variation of quasi saturated hydraulic conductivity of soil is often ascribed to changing fraction of the entrapped air and it is not considered in standard theory of water flow in porous media. Variation of quasi steady state flow was observed during ponded infiltration experiments on three small undisturbed samples of coarse sandy loam. Two main flow irregularities typical for soil under study were detected for two soil samples during recurrent ponding experiment: (1) Gradual decrease of the quasi-saturated hydraulic conductivity (Kqs) soon after outflow appeared and (2) lower Kqs during the second infiltration run. The third sample didn't produce similar variability. Series of neutron tomography images of the sample taken during quasi-steady state stage of the first infiltration run showed air trapping in many of large pores and cavities. Furthermore, many of entrapped air bubbles increased in volume during the course of the first infiltration run. Further entrapped air redistribution has been detected during the second run. The fraction of the entrapped air was calculated for series of tomography images taken during the experiment. The increase of entrapped air bubbles volumetric fraction by only 0.005 was accompanied by decrease of quasi-saturated hydraulic conductivity by up to 50% of the initial value. The experimental results support the hypothesis that the effect of the gradual decrease of Kqs is caused by entrapped air redistribution and build-up of bubbles in preferential pathways. The trapped air may thus restrict the preferential flow pathways and cause lower infiltration and outflow flux rates.
- Temporal variation of quasi saturated hydraulic conductivity of soil is often ascribed to changing fraction of the entrapped air and it is not considered in standard theory of water flow in porous media. Variation of quasi steady state flow was observed during ponded infiltration experiments on three small undisturbed samples of coarse sandy loam. Two main flow irregularities typical for soil under study were detected for two soil samples during recurrent ponding experiment: (1) Gradual decrease of the quasi-saturated hydraulic conductivity (Kqs) soon after outflow appeared and (2) lower Kqs during the second infiltration run. The third sample didn't produce similar variability. Series of neutron tomography images of the sample taken during quasi-steady state stage of the first infiltration run showed air trapping in many of large pores and cavities. Furthermore, many of entrapped air bubbles increased in volume during the course of the first infiltration run. Further entrapped air redistribution has been detected during the second run. The fraction of the entrapped air was calculated for series of tomography images taken during the experiment. The increase of entrapped air bubbles volumetric fraction by only 0.005 was accompanied by decrease of quasi-saturated hydraulic conductivity by up to 50% of the initial value. The experimental results support the hypothesis that the effect of the gradual decrease of Kqs is caused by entrapped air redistribution and build-up of bubbles in preferential pathways. The trapped air may thus restrict the preferential flow pathways and cause lower infiltration and outflow flux rates. (en)
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| Title
| - Investigating flow instabilities caused by entrapped air: Infiltration-outflow experiment monitored by neutron tomography
- Investigating flow instabilities caused by entrapped air: Infiltration-outflow experiment monitored by neutron tomography (en)
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| skos:prefLabel
| - Investigating flow instabilities caused by entrapped air: Infiltration-outflow experiment monitored by neutron tomography
- Investigating flow instabilities caused by entrapped air: Infiltration-outflow experiment monitored by neutron tomography (en)
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| skos:notation
| - RIV/68407700:21110/12:00201386!RIV13-GA0-21110___
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| http://linked.open...avai/riv/aktivita
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| http://linked.open...avai/riv/aktivity
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| http://linked.open...vai/riv/dodaniDat
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| http://linked.open...aciTvurceVysledku
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| http://linked.open.../riv/druhVysledku
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| http://linked.open...iv/duvernostUdaju
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| http://linked.open...titaPredkladatele
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| http://linked.open...dnocenehoVysledku
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| http://linked.open...ai/riv/idVysledku
| - RIV/68407700:21110/12:00201386
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| http://linked.open...riv/jazykVysledku
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| http://linked.open.../riv/klicovaSlova
| - neutron imaging; visualization; hydraulic conductivity; soil (en)
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| http://linked.open.../riv/klicoveSlovo
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| http://linked.open...ontrolniKodProRIV
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| http://linked.open...in/vavai/riv/obor
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| http://linked.open...ichTvurcuVysledku
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| http://linked.open...cetTvurcuVysledku
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| http://linked.open...vavai/riv/projekt
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| http://linked.open...UplatneniVysledku
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| http://linked.open...iv/tvurceVysledku
| - Císlerová, Milena
- Sněhota, Michal
- Sobotková, Martina
- Novotný, P.
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| http://localhost/t...ganizacniJednotka
| |
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