sphere
is a 3D discrete element method algorithm utilizing CUDA. sphere
allows for optional simulation of two-way coupled fluid flow using the
Navier-Stokes or Darcy formulations.
A powerful Nvidia GPU with proper support for double precision floating is
highly recommended. sphere
has been tested with the Nvidia Tesla K20 and
Nvidia Tesla M2050 GPUs.
sphere
is licensed under the GNU General Public License, v.3.
See LICENSE.txt for more information.
2016-08-16: Scale-invariant grain-contact model implemented based on Ergenzinger
et al 2010 and Obermayr et al 2013. To use specify a positive Young's modulus
with setYoungsModulus(<value>)
in the Python module. This overrides any
contact stiffnesses specified in k_n
and k_t
. This command should be
used before the timestep length is determined in initTemporal(...)
.
2016-08-14: Dirichlet and von Neumann horizontal boundary conditions implemented in addition to horizontal periodicity for the Darcian fluid solver.
2015-09-06: A new flux boundary condition has been added to the Darcy fluid solver.
2014-11-05: A Darcy solver has been added as an alternative to the Navier-Stokes
solver of the fluid phase. It can be selected with e.g. initFluid(cfd_solver =
1)
in the Python module.
2014-07-28: Fluid flow is no longer simulated in a separate program. Use
sphere
with the command line argument -f
or --fluid
instead.
2014-07-05: Fluid phase now discretized on a staggered grid which increases accuracy and stability.
2014-03-25: Fluid phase in master
branch simulated by the full Navier-Stokes
equations.
2014-03-09: The writebin
member function of the sim
class is now
implicitly called when calling the run
member function.
2014-03-09: The main sphere class (formerly spherebin
) has been renamed to
sim
.
2014-01-20: Version fingerprints have been added to the input/output binary
files, and causes old files to be incompatible with either sphere
or
sphere.py
.
2014-01-25: The description of the installation procedure is moved to the general documentation.
2013-03-13: Sphere has been updated to work with CUDA 5.0 or newer only.
See the separate documentation for general reference and installation instructions. The documentation is by default available in the html and pdf formats.
All examples are visualized using ParaView.
![Shear test](doc/sphinx/img/shear.png)
Shear of a dense particle assemblage. Top left: particles colored by initial positions, top center: particles colored by horizontal velocity, top right: particles colored by pressure. Bottom left: fluid pressures, bottom center: porosities, bottom right: porosity changes.
sphere
has been used to produce results in the following scientific
publications and presentations:
- Damsgaard, A., D.L. Egholm, L.H. Beem, S. Tulaczyk, N.K. Larsen, J.A. Piotrowski, and M.R. Siegfried (2016), Ice flow dynamics forced by water pressure variations in subglacial granular beds, Geophysical Research Letters, 43, doi:10.1002/2016GL071579.
- Damsgaard, A., D.L. Egholm, J.A. Piotrowski, S. Tulaczyk, N.K. Larsen, and C.F. Brædstrup (2015), A new methodology to simulate subglacial deformation of water-saturated granular material, The Cryosphere, 9, 2183-2200, doi:10.5194/tc-9-2183-2015.
- Damsgaard, A., D.L. Egholm, J.A. Piotrowski, S. Tulaczyk, N.K. Larsen, and C.F. Brædstrup (2014), Numerical modeling of particle-fluid mixtures in a subglacial setting. Poster at Americal Geophysical Union Fall Meeting.
- Damsgaard, A., D.L. Egholm, J.A. Piotrowski, S. Tulaczyk, N.K. Larsen, and K. Tylmann (2013), Discrete element modeling of subglacial sediment deformation, J. Geophys. Res. Earth Surf., 118, 2230–2242, doi:10.1002/2013JF002830.
- Damsgaard, A., D.L. Egholm, J.A. Piotrowski, S. Tulaczyk, and N.K. Larsen (2013), Discrete element modeling of subglacial sediment deformation. Talk at American Geophysical Fall Meeting 2013.
- Damsgaard, A., D.L. Egholm, J.A. Piotrowski, S. Tulaczyk, and N.K. Larsen (2013), Numerical modelling of granular subglacial deformation using the discrete element method. Poster at European Geosciences Union General Assembly 2013.
- Damsgaard, A., D.L. Egholm, J.A. Piotrowski, and S. Tulaczyk (2012), Discrete element modelling of subglacial sediment deformation. Poster at European Geosciences Union General Assembly 2012.
- Damsgaard, A., D.L. Egholm, and J.A. Piotrowski (2011), Numerical modelling of sediment deformation by glacial stress. Poster at International Union for Quaternary Research Congress 2011.
- Damsgaard, A., D.L. Egholm, and J.A. Piotrowski (2011), Numerical modelling of subglacial sediment deformation. Poster at European Geosciences Union General Assembly 2011.
Anders Damsgaard, [email protected], webpage.
With contributions from Cooper Elsworth.