Source code for espressomd.lbboundaries

# Copyright (C) 2010-2022 The ESPResSo project
# This file is part of ESPResSo.
# ESPResSo is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# ESPResSo is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <>.
from .script_interface import ScriptObjectList, ScriptInterfaceHelper, script_interface_register
from .__init__ import has_features

if any(has_features(i) for i in ["LB_BOUNDARIES", "LB_BOUNDARIES_GPU"]):
[docs] @script_interface_register class LBBoundaries(ScriptObjectList): """ Creates a set of lattice-Boltzmann boundaries. Methods ------- size() Get the number of active boundaries. empty() Return ``True`` if there are not active boundaries. clear() Clear the list of boundaries. """ _so_name = "LBBoundaries::LBBoundaries" _so_bind_methods = ("size", "empty", "clear")
[docs] def add(self, *args, **kwargs): """ Adds a boundary to the set of boundaries. Either pass a valid boundary as argument, or a valid set of parameters to create a boundary. """ if len(args) == 1: if isinstance(args[0], LBBoundary): lbboundary = args[0] else: raise TypeError( "Either a LBBoundary object or key-value pairs for the parameters of a LBBoundary object need to be passed.") else: lbboundary = LBBoundary(**kwargs) self.call_method("add", object=lbboundary) return lbboundary
[docs] def remove(self, lbboundary): """ Removes a boundary from the set. Parameters ---------- lbboundary : :obj:`LBBoundary` The boundary to be removed from the set. """ self.call_method("remove", object=lbboundary)
[docs] @script_interface_register class LBBoundary(ScriptInterfaceHelper): """ Creates a LB boundary from a shape. The fluid velocity is limited to :math:`v_{\\mathrm{max}} = 0.20` (see *quasi-incompressible limit* in :cite:`kruger17a`, chapter 7, page 272), which corresponds to Mach 0.35. The relative error in the fluid density between a compressible fluid and an incompressible fluid at Mach 0.30 is less than 5% (see *constant density assumption* in :cite:`kundu01a` chapter 16, page 663). Since the speed of sound is :math:`c_s = 1 / \\sqrt{3}` in LB velocity units in a D3Q19 lattice, the velocity limit at Mach 0.30 is :math:`v_{\\mathrm{max}} = 0.30 / \\sqrt{3} \\approx 0.17`. At Mach 0.35 the relative error is around 6% and :math:`v_{\\mathrm{max}} = 0.35 / \\sqrt{3} \\approx 0.20`. Parameters ---------- shape : :obj:`espressomd.shapes.Shape` The shape from which to build the boundary. velocity : (3,) array_like of :obj:`float`, optional The boundary slip velocity. By default, a velocity of zero is used (no-slip boundary condition). """ _so_name = "LBBoundaries::LBBoundary" _so_bind_methods = ("get_force",)