sphere is a 3D discrete element method algorithm utilizing CUDA.
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
sphere has been tested with Nvidia Tesla GPUs, and has
successfully been employed on the clusters Grendel (Aarhus University), ICME (Stanford
(San Diego Supercomputing Center), Bridges (Portland
Supercomputing Center), and Stampede
(Texas Advanced Supercomputing Center).
sphere is licensed under the GNU General Public License, v.3.
See LICENSE.txt for more information.
Important release notes
2017-09-07: CUDA 8 comes with new requirements to the host CC/C++ compiler. If GCC5 is not available on the system, run the following command before invoking make:
export CC=$(which clang-3.8) && export CXX=$(which clang++-3.8) && cmake .
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
setYoungsModulus(<value>) in the Python module. This overrides any
contact stiffnesses specified in
k_t. This command should be
used before the timestep length is determined in
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.
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
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
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
2014-01-20: Version fingerprints have been added to the input/output binary
files, and causes old files to be incompatible with either
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.
All examples are visualized using ParaView.
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., J. Suckale, J. A. Piotrowski, M. Houssais, M. R. Siegfried, H. A. Fricker (2017), Sediment behavior controls equilibrium width of subglacial channels, Journal of Glaciology, doi:10.1017/jog.2017.71.
- Damsgaard, A., A. Cabrales-Vargas, J. Suckale, and L. Goren (2017), The coupled dynamics of meltwater percolation and granular deformation in the sediment layer underlying parts of the big ice sheets, Poromechanics VI, doi:10.1061/9780784480779.024.
- 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.
If you use sphere for scientific publications, please get in touch to add your entry to the above list. It would be appreciated if the sphere development is acknowledged by citing one of the above Damsgaard et al. publications.