depot.py

# MigFlow - Copyright (C) <2010-2018>
# <Universite catholique de Louvain (UCL), Belgium
#  Universite de Montpellier, France>
#
# List of the contributors to the development of MigFlow: see AUTHORS file.
# Description and complete License: see LICENSE file.
#
# This program (MigFlow) is free software:
# you can redistribute it and/or modify it under the terms of the GNU Lesser General
# Public License as published by the Free Software Foundation, either version
# 3 of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program (see COPYING and COPYING.LESSER files).  If not,
# see <http://www.gnu.org/licenses/>.

#!/usr/bin/env python

# TESTCASE DESCRIPTION
# Bidimensional particles sedimentation in fluid


from migflow import fluid
from migflow import scontact
from migflow import time_integration

import numpy as np
import os
import time
import shutil
import random

def genInitialPosition(filename, r, H, ly, lx, rhop) :
    """Set all the particles centre positions and create the particles objects to add in the computing structure

    Keyword arguments:
    filename -- name of the output file
    r -- max radius of the particles
    H -- domain height
    ly - particles area height
    lx -- particles area width
    rhop -- particles density
    """
    # Particles structure builder
    p = scontact.ParticleProblem(2)
    # Load mesh.msh file specifying physical boundaries names
    p.load_msh_boundaries("mesh.msh", ["Top", "Lateral","Bottom"])

    #Definition of the points where the particles are located
    x = np.arange(-lx/2+r-1e-8, lx/2-r+1e-8, 2*r)
    y = np.arange(H/2-r, H/2-ly+r, -2*r)
    x, y = np.meshgrid(x, y)
    x = x.flat
    y = y.flat
    # Add a grain at each centre position
    for i in range(len(x)) :
        p.add_particle((x[i], y[i]), r, r**2 * np.pi * rhop)
    p.write_vtk(filename,0,0)

# Define output directory
outputdir = "output"
if not os.path.isdir(outputdir) :
    os.makedirs(outputdir)

# Physical parameters
g = np.array([0,-9.81])                         # gravity
r = 1e-3                                        # particles radius
rhop = 1500                                     # particles density
rho = 1000                                      # fluid density
nu = 1e-6                                       # kinematic viscosity

# Numerical parameters
outf = 5                                        # number of iterations between output files
dt = 2.5e-3                                     # time step
tEnd = 100                                      # final time

# Geometrical parameters
ly = 1e-1                                       # particles area height
lx = 4e-1                                       # particles area widht
H = 0.6                                         # domain height

#
# PARTICLE PROBLEM
#
# Initialise particles
genInitialPosition(outputdir, r, H, ly, lx, rhop)
p = scontact.ParticleProblem(2)
p.read_vtk(outputdir,0)

print("r = %g, m = %g\n" %  (p.r()[0], p.mass()[0]))
print("RHOP = %g" % rhop)

# Initial time and iteration
t         =  0
ii        =  0

#
# FLUID PROBLEM
#
fluid = fluid.FluidProblem(2,g,[nu*rho],[rho])
# Set the mesh geometry for the fluid computation
fluid.load_msh("mesh.msh")
fluid.set_wall_boundary("Bottom")
fluid.set_wall_boundary("Lateral")
fluid.set_wall_boundary("Top",pressure=0)
# Set location of the particles in the mesh and compute the porosity in each computation cell
fluid.set_particles(p.mass(), p.volume(), p.state(), p.contact_forces(),init=True)
fluid.export_vtk(outputdir,0,0)
p.write_vtk(outputdir, 0, 0)

tic = time.time()

G = np.zeros((p.n_particles(),2))
G[:,1] = p.mass()[:,0]*g[1]
#
# COMPUTATION LOOP
#
while t < tEnd :
    time_integration.iterate(fluid, p, dt, min_nsub=5, external_particles_forces=G)
    t += dt

    # Output files writting
    if ii %outf == 0 :
        ioutput = int(ii/outf) + 1
        p.write_vtk(outputdir, ioutput, t)
        fluid.export_vtk(outputdir, t, ioutput)
    ii += 1
    print("%i : %.2g/%.2g (cpu %.6g)" % (ii, t, tEnd, time.time() - tic))