commit c73252552b198bf7c553a34763e660352e5488f7
parent f647c74f68d9feff3da7a34d86586529bf7b7a89
Author: Anders Damsgaard <anders@adamsgaard.dk>
Date: Tue, 25 Jun 2019 09:40:44 +0200
Rewrite abstract
Diffstat:
1 file changed, 17 insertions(+), 9 deletions(-)
diff --git a/continuum-granular-manuscript1.tex b/continuum-granular-manuscript1.tex
@@ -38,14 +38,12 @@ maxcitenames=2, backend=bibtex8]{biblatex}
\maketitle
\begin{abstract}
-The mechanical properties of subglacial sediments govern the physical behavior of glaciers and ice sheets moving over sedimentary beds.
-Laboratory experiments and field observations have established that subglacial sediments in general follow the non-linear Mohr–Coulomb rheological behavior that is typical for granular sediments.
-However, the Mohr–Coulomb rheology does not by itself describe the spatial distribution of strain, nor the rate-dependent friction and dilation observed in inertial granular flows.
-Discrete-element models quantify these mechanical properties in simple granular materials, and can provide insight into the micro-mechanics and transient effects during deformation of sediment and porewater.
-However, the associated computational costs are too intense to allow for coupling to glacier models or for analyzing larger-scale subglacial bedform evolution.
-Here, we present progress toward a water-saturated granular continuum model that is consistent with laboratory experiments and generalizes to Mohr–Coulomb behavior at large scales.
-Our formulation draws heavily on recent advances in the field of granular physics that have produced continuum formulations for dry granular flows.
-We generalize these previous models to a water-saturated granular flow, by comparing the behavior of the continuum formulation to grain-scale simulations with the discrete-element method and to published results of laboratory till deformation.
+Subglacial sediment mechanics are of primary importance to glacier and ice-sheet flow patterns at high basal water pressures.
+Till yield strength follows the non-linear Mohr–Coulomb rheology, but that does not by itself describe the spatial distribution of strain.
+Here, we present a water-saturated granular continuum model that is consistent with laboratory experiments on till and follows Mohr–Coulomb behavior at large scales.
+The model is sufficiently lightweight to allow for coupled glacier-sediment-hydrology modeling.
+The strain distribution and sediment transport arises from principal sediment properties, and for the first time allows for a quantification of sediment advection during shear.
+We show that past pulses in water pressure can transfer shear away from the ice-bed interface and deep into the bed.
\end{abstract}
@@ -146,12 +144,22 @@ We then use Jacobian iterations to find an implicit solution to the same equatio
For the final pressure field at $t + \Delta t$ we mix the explicit and implicit solutions with equal weight, which is known as the Crank-Nicholson method \citep[e.g.][]{Patankar1980, Ferziger2002, Press2007}.
The method is unconditionally stable and second-order accurate in time and space.
+\section{Results}%
+\label{sec:results}
+
+
+\section{Discussion}%
+\label{sec:discussion}
+
+
+\section{Conclusion}%
+\label{sec:conclusion}
\section*{Appendix}%
\label{sec:appendix}
The source code for the grain-water model is available at \url{https://gitlab.com/admesg/1d_fd_simple_shear}.
-All figures and data can be reproduced by following the instructions in the experiment repository for this publication, available at \url{https://gitlab.com/admesg/continuum_granular_exp_manus1}.
+All results and figures can be reproduced by following the instructions in the experiment repository for this publication, available at \url{https://gitlab.com/admesg/continuum_granular_exp_manus1}.
%% Bibliography
\printbibliography{}
