This package contains a LAMMPS implementation of a background Lattice-Boltzmann fluid, which can be used to model MD particles influenced by hydrodynamic forces. Details of the package is describe in : C. Denniston, N. Afrasiabian, M.G. Cole-Andre, F.E. Mackay, S.T.T. Ollila, and T. Whitehead, LAMMPS lb/fluid fix version 2: Improved Hydrodynamic Forces Implemented into LAMMPS through a lattice-Boltzmann fluid, Computer Physics Communications 275 (2022) 108318. or https://doi.org/10.1016/j.cpc.2022.108318 See the doc page for the fix lb/fluid command to get started, and see brief descriptions of other fixes below, each of which have their own doc page. There are example scripts for using this package in examples/PACKAGES/latboltz. IMPORTANT NOTE: This package can only be used if LAMMPS is compiled with MPI (i.e. the serial makefile should not be used to compile the code). Also, several of the test examples provided make use of the rigid fix and molecule packages. Therefore, these should be included in the LAMMPS build (see the "Including/excluding packages" section of the LAMMPS manual). The creators of this package are as follows: Frances Mackay Santtu Ollila Tyson Whitehead Colin Denniston, cdennist@uwo.ca University of Western Ontario -------------------------------------------------------------------------- Fixes provided by this package: fix_lb_fluid.cpp: fix used to create the lattice-Boltzmann fluid on a grid covering the LAMMPS simulation domain. fix_momentum_lb.cpp: fix used to subtract off the total (atom plus fluid) linear momentum from the system. fix_viscous_lb.cpp: fix to add the fluid force to the atoms when using a built-in LAMMPS integrator.