Modelling of the flow of anisotropic polar ice and first applications to the Dome-C ice core
The ice crystal is one of the most anisotropic natural materials. Observations of polar ice show that the crystals are orientated along very marked privileged directions and that the fabric of the ice polycristal is the result of the strain history that the polycristal has undergone. The macroscopic...
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Format: | Doctoral or Postdoctoral Thesis |
Language: | French |
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HAL CCSD
2006
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Online Access: | https://theses.hal.science/tel-00125476 https://theses.hal.science/tel-00125476/document https://theses.hal.science/tel-00125476/file/these.pdf |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Université Savoie Mont Blanc: HAL |
op_collection_id |
ftunivsavoie |
language |
French |
topic |
ice-sheet self consistent model strain induced anisotropy finite elements orientation tensors Homogenization Calotte polaire Modèle auto-cohérent Anisotropie induite évolutive Eléments finis Tenseurs d'orientation Homogénéisation [SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph] |
spellingShingle |
ice-sheet self consistent model strain induced anisotropy finite elements orientation tensors Homogenization Calotte polaire Modèle auto-cohérent Anisotropie induite évolutive Eléments finis Tenseurs d'orientation Homogénéisation [SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph] Gillet-Chaulet, Fabien Modelling of the flow of anisotropic polar ice and first applications to the Dome-C ice core |
topic_facet |
ice-sheet self consistent model strain induced anisotropy finite elements orientation tensors Homogenization Calotte polaire Modèle auto-cohérent Anisotropie induite évolutive Eléments finis Tenseurs d'orientation Homogénéisation [SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph] |
description |
The ice crystal is one of the most anisotropic natural materials. Observations of polar ice show that the crystals are orientated along very marked privileged directions and that the fabric of the ice polycristal is the result of the strain history that the polycristal has undergone. The macroscopic polycristal behaviour depends on the fabric and can be strongly anisotropic. It has been shown that anisotropy can introduce the occurrence of stratigraphy disturbances and influences strongly the flow of the ice sheet. The aim of this work is to build an ice flow model for anisotropic ice and the evolution of its fabric. To this end, we model the ice monocrystal as a transversely isotropic continuous medium around its c-axis and we compare it with a slip-planes grain model. The ice fabric is described in a continuous way by the second order orientation tensor and a closure approximation for the fourth ordre orientation tensor. By homogenization, assuming uniform stresses or strain-rates, we obtain analytical solutions for the polycrystal behaviour and the evolution of its fabric. From these solutions, we derive a linear orthotropic flow law for the ice polycrystal and an equation for the evolution of the second order orientation tensor. These equations are able to reproduce the results of the self-consistent model using a discrete fabric description, with an important improvement as regards the computing time and the number of variables necessary to describe the fabric. These equations are then implemented in a finite element code, used for simulating the flow of an ice sheet with strain-induced evolving anisotropy. By performing synthetic tests, we show the influence of anisotropy on the ice flow. Finally, through our model results, we propose an interpretation of the Dome-C ice-core fabric data. Le cristal de glace est l'un des matériaux naturels les plus anisotropes. L'analyse des glaces polaires indique que les cristaux s'orientent selon des directions privilégiées et que la fabrique (distribution des ... |
author2 |
Laboratoire de glaciologie et géophysique de l'environnement (LGGE) Observatoire des Sciences de l'Univers de Grenoble (OSUG) Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) Université Joseph-Fourier - Grenoble I Jacques Meyssonnier(meysonnier@lgge.obs.ujf-grenoble.fr) |
format |
Doctoral or Postdoctoral Thesis |
author |
Gillet-Chaulet, Fabien |
author_facet |
Gillet-Chaulet, Fabien |
author_sort |
Gillet-Chaulet, Fabien |
title |
Modelling of the flow of anisotropic polar ice and first applications to the Dome-C ice core |
title_short |
Modelling of the flow of anisotropic polar ice and first applications to the Dome-C ice core |
title_full |
Modelling of the flow of anisotropic polar ice and first applications to the Dome-C ice core |
title_fullStr |
Modelling of the flow of anisotropic polar ice and first applications to the Dome-C ice core |
title_full_unstemmed |
Modelling of the flow of anisotropic polar ice and first applications to the Dome-C ice core |
title_sort |
modelling of the flow of anisotropic polar ice and first applications to the dome-c ice core |
publisher |
HAL CCSD |
publishDate |
2006 |
url |
https://theses.hal.science/tel-00125476 https://theses.hal.science/tel-00125476/document https://theses.hal.science/tel-00125476/file/these.pdf |
genre |
ice core Ice Sheet |
genre_facet |
ice core Ice Sheet |
op_source |
https://theses.hal.science/tel-00125476 Mécanique [physics.med-ph]. Université Joseph-Fourier - Grenoble I, 2006. Français. ⟨NNT : ⟩ |
op_relation |
tel-00125476 https://theses.hal.science/tel-00125476 https://theses.hal.science/tel-00125476/document https://theses.hal.science/tel-00125476/file/these.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1797584686319403008 |
spelling |
ftunivsavoie:oai:HAL:tel-00125476v1 2024-04-28T08:24:18+00:00 Modelling of the flow of anisotropic polar ice and first applications to the Dome-C ice core MODELISATION DE L'ECOULEMENT DE LA GLACE POLAIRE ANISOTROPE ET PREMIERES APPLICATIONS AU FORAGE DE DOME C Gillet-Chaulet, Fabien Laboratoire de glaciologie et géophysique de l'environnement (LGGE) Observatoire des Sciences de l'Univers de Grenoble (OSUG) Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) Université Joseph-Fourier - Grenoble I Jacques Meyssonnier(meysonnier@lgge.obs.ujf-grenoble.fr) 2006-12-01 https://theses.hal.science/tel-00125476 https://theses.hal.science/tel-00125476/document https://theses.hal.science/tel-00125476/file/these.pdf fr fre HAL CCSD tel-00125476 https://theses.hal.science/tel-00125476 https://theses.hal.science/tel-00125476/document https://theses.hal.science/tel-00125476/file/these.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-00125476 Mécanique [physics.med-ph]. Université Joseph-Fourier - Grenoble I, 2006. Français. ⟨NNT : ⟩ ice-sheet self consistent model strain induced anisotropy finite elements orientation tensors Homogenization Calotte polaire Modèle auto-cohérent Anisotropie induite évolutive Eléments finis Tenseurs d'orientation Homogénéisation [SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph] info:eu-repo/semantics/doctoralThesis Theses 2006 ftunivsavoie 2024-04-11T01:01:27Z The ice crystal is one of the most anisotropic natural materials. Observations of polar ice show that the crystals are orientated along very marked privileged directions and that the fabric of the ice polycristal is the result of the strain history that the polycristal has undergone. The macroscopic polycristal behaviour depends on the fabric and can be strongly anisotropic. It has been shown that anisotropy can introduce the occurrence of stratigraphy disturbances and influences strongly the flow of the ice sheet. The aim of this work is to build an ice flow model for anisotropic ice and the evolution of its fabric. To this end, we model the ice monocrystal as a transversely isotropic continuous medium around its c-axis and we compare it with a slip-planes grain model. The ice fabric is described in a continuous way by the second order orientation tensor and a closure approximation for the fourth ordre orientation tensor. By homogenization, assuming uniform stresses or strain-rates, we obtain analytical solutions for the polycrystal behaviour and the evolution of its fabric. From these solutions, we derive a linear orthotropic flow law for the ice polycrystal and an equation for the evolution of the second order orientation tensor. These equations are able to reproduce the results of the self-consistent model using a discrete fabric description, with an important improvement as regards the computing time and the number of variables necessary to describe the fabric. These equations are then implemented in a finite element code, used for simulating the flow of an ice sheet with strain-induced evolving anisotropy. By performing synthetic tests, we show the influence of anisotropy on the ice flow. Finally, through our model results, we propose an interpretation of the Dome-C ice-core fabric data. Le cristal de glace est l'un des matériaux naturels les plus anisotropes. L'analyse des glaces polaires indique que les cristaux s'orientent selon des directions privilégiées et que la fabrique (distribution des ... Doctoral or Postdoctoral Thesis ice core Ice Sheet Université Savoie Mont Blanc: HAL |