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COPSS

COPSS (Continuum Particle Simulation Suite) is an open source, libMesh based, software for continuum-particle simulations. The package is designed to be easy to use, extensible, and scalable. It currently includes three modules, COPSS-Hydrodynamics to solve hydrodynamic interactions in colloidal suspensions, COPSS-Polarization to solve electrostatic interactions in heterogeneous dielectric media, and COPSS-LC to model the relaxation of nematic liquid crystals. . The algorithms beneath COPSS have been published or under-review, but the code framework, user-interface, etc., are still rough. We are working on improving COPSS and appreciate your contributions.

COPSS-LC v1.1

COPSS-LC solves the isoentropic relaxation (Ginzburg-Landau) of a Landau-de Gennes type free energy functional. It is based on an efficient $O(N)$ computational approach to model arbitrary-shaped sharp interfaces separating dielectrics with spatially different dielectric permittivities. A parallel boundary element Poisson solver is the center of the algorithm.

Installation

COPSS-LC is written in Fortran, to ease understanding of the underlying model. The requirements for installation are those required by the compiler of choice. For development we used the Intel Fortran Compiler.

For visualization purposes, we provide a subroutine that creates vtk files to be read by Paraview, and that contain the information of the order parameter S and director field n. For instructions on visualization we direct the reader to the manual of Paraview.

Build documentation

This software requires compilation using either Intel Fortran Compiler or GFortran. You can further build the documentation from doxygen/ directory. Make sure you have Doxygen ready:

doxygen Doxyfile.bak

Then you can view the documentation in IE browser:

google-chrome html.index.html

What's next

  • Coupling COPSS with molecular dynamics package LAMMPS
  • Coupling COPSS with hydrodynamics calculations (COPSS-Hydrodynamics developed by COPSS team).
  • More user friendly interface.
  • etc...

Contribution

Liquid crystal research has advanced in the past few years thanks to the collaboration between theory, simulations, and experiments. From the simulations contribution at the continuum scale, the models have been published for more than a decade but there are no free available codes that show the details on how to perform the simulations. With COPSS-LC we want to make basic codes available for the community, so research focused on LCs is more accessible.

Contact

Algorithm

This code is built following some of the details published by Ravnik et al. with a few alterations to improve numerical stability. In general, it follows the methodology as published in Homeotropic nano-particle assembly on degenerate planar nematic interfaces: films and droplets for the Ginzburg-Landau relaxation. More details on the model and method implementation can be followed in the documentation.

Main contributors

License

  • The codes are open-source and distributed under the GNU GPL license, and may not be used for any commercial or for-profit purposes without our permission.