avalanch1fluidnofriction.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:
# Collapsing of a grain column in fluid. 
# This test case cannot be runned on its own, it requires the output files of the depot test case (../depot/dep.py) to create a compact column as initial situation
# Positions, masses and radii of grains are setted in the depot.py file.
from migflow import fluid
from migflow import scontact

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

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

# Physical parameters
g = -9.81                                 # gravity
rhop = 1500                               # grains density
rhof = 1000                               # fluid density
nuf = 1e-6                                # kinematic fluid viscosity

# Numerical parameters
outf = 10                                 # number of iterations between output files
dt = 1e-4                                 # time step
tEnd = 10                                 # final time

# 
# PARTICLES PROBLEM
#
# Particles container structure builder to load file created with depot.py.
p1 = scontact.ParticleProblem(2)
# Use particles deposit computed by the depot.py file of "depot" folder.
p1.read_vtk("../depot/output",25)
# New particles container structure builder to set other boundary conditions than in depot.py.
p = scontact.ParticleProblem(2)
p.load_msh_boundaries("mesh.msh", ["Top", "Bottom", "Left", "Right"])
for i in range(len(p1.position()[:,0])):
    p.add_particle((p1.position()[i,0], p1.position()[i,1]), p1.r()[i], p1.r()[i]**2 * np.pi * rhop)
p.write_vtk(outputdir, 0, 0)

# Initial time and iteration.
t = 0
ii = 0

#
# FLUID PROBLEM
#
# Fluid structure builder.
fluid = fluid.FluidProblem(2,g,[nuf*rhof],[rhof])
# Set the mesh geometry for the fluid computation.
fluid.load_msh("mesh.msh")
fluid.set_wall_boundary("Bottom")
fluid.set_wall_boundary("Left")
fluid.set_wall_boundary("Top",pressure=0)
fluid.set_wall_boundary("Right")
# Set locations of the grains in the mesh and compute the porosity in each computation cell.
fluid.set_particles(p.mass(), p.volume(), p.position(), p.velocity())
# Write output files for post-visualization.
fluid.export_vtk(outputdir,0,0)

tic = time.time()
fluid.set_particles(p.mass(), p.volume(), p.position(), p.velocity())

# 
# COMPUTATION LOOP
# 
while t < tEnd : 
    # Solve averaged Navier-Stokes equations.
    fluid.implicit_euler(dt)

    # Adaptation of the mesh.
    if (ii%15==0 and ii != 0):
       fluid.adapt_mesh(1e-2, 3e-3, 10000)

    # Computation of the new velocities.
    forces = fluid.compute_node_force(dt)
    vn = p.velocity() + forces*dt/p.mass()
    vmax = np.max(np.hypot(vn[:, 0], vn[:, 1]))
    # Number of contact sub time step.
    nsub = max(1, int(np.ceil((vmax * dt * 4)/min(p.r()))))
    print("NSUB", nsub,"VMAX",vmax, "VMAX * dt", vmax * dt, "r", min(p.r()))
    # NLGS iterations.
    for i in range(nsub) :
        p.iterate(dt/nsub, forces)  

    t += dt
    fluid.set_particles(p.mass(), p.volume(), p.position(), p.velocity())

    # Output files writing.
    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))