/usr/lib/python2.7/dist-packages/PySPH-1.0a4.dev0-py2.7-linux-x86_64.egg/pysph/examples/surface_tension/circular_droplet.py is in python-pysph 0~20160514.git91867dc-4build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 | """Curvature computation for a circular droplet. (5 seconds)
For particles distributed in a box, an initial circular interface is
distinguished by coloring the particles within a circle. The resulting
equations can then be used to check for the numerical curvature and
discretized dirac-delta function based on this artificial interface.
"""
import numpy
# Particle generator
from pysph.base.utils import get_particle_array
from pysph.base.kernels import QuinticSpline
# SPH Equations and Group
from pysph.sph.equation import Group
from pysph.sph.wc.viscosity import ClearyArtificialViscosity
from pysph.sph.wc.transport_velocity import SummationDensity, MomentumEquationPressureGradient,\
SolidWallPressureBC, SolidWallNoSlipBC, \
StateEquation, MomentumEquationArtificialStress, MomentumEquationViscosity
from pysph.sph.surface_tension import ColorGradientUsingNumberDensity, \
InterfaceCurvatureFromNumberDensity, ShadlooYildizSurfaceTensionForce,\
SmoothedColor, AdamiColorGradient, AdamiReproducingDivergence,\
MorrisColorGradient
from pysph.sph.gas_dynamics.basic import ScaleSmoothingLength
# PySPH solver and application
from pysph.solver.application import Application
from pysph.solver.solver import Solver
# Integrators and Steppers
from pysph.sph.integrator_step import TransportVelocityStep
from pysph.sph.integrator import PECIntegrator
# Domain manager for periodic domains
from pysph.base.nnps import DomainManager
# problem parameters
dim = 2
domain_width = 1.0
domain_height = 1.0
# numerical constants
wavelength = 1.0
wavenumber = 2*numpy.pi/wavelength
rho0 = rho1 = 1000.0
rho2 = 1*rho1
U = 0.5
sigma = 1.0
# discretization parameters
dx = dy = 0.0125
dxb2 = dyb2 = 0.5 * dx
hdx = 1.5
h0 = hdx * dx
rho0 = 1000.0
c0 = 20.0
p0 = c0*c0*rho0
nu = 0.01
# set factor1 to [0.5 ~ 1.0] to simulate a thick or thin
# interface. Larger values result in a thick interface. Set factor1 =
# 1 for the Morris Method I
factor1 = 1.0
factor2 = 1./factor1
# correction factor for Morris's Method I. Set with_morris_correction
# to True when using this correction.
epsilon = 0.01/h0
# time steps
dt_cfl = 0.25 * h0/( 1.1*c0 )
dt_viscous = 0.125 * h0**2/nu
dt_force = 1.0
dt = 0.9 * min(dt_cfl, dt_viscous, dt_force)
tf = 5*dt
staggered = True
class CircularDroplet(Application):
def create_domain(self):
return DomainManager(
xmin=0, xmax=domain_width, ymin=0, ymax=domain_height,
periodic_in_x=True, periodic_in_y=True)
def create_particles(self):
if staggered:
x1, y1 = numpy.mgrid[ dxb2:domain_width:dx, dyb2:domain_height:dy ]
x2, y2 = numpy.mgrid[ dx:domain_width:dx, dy:domain_height:dy ]
x1 = x1.ravel(); y1 = y1.ravel()
x2 = x2.ravel(); y2 = y2.ravel()
x = numpy.concatenate( [x1, x2] )
y = numpy.concatenate( [y1, y2] )
volume = dx*dx/2
else:
x, y = numpy.mgrid[ dxb2:domain_width:dx, dyb2:domain_height:dy ]
x = x.ravel(); y = y.ravel()
volume = dx*dx
m = numpy.ones_like(x) * volume * rho0
rho = numpy.ones_like(x) * rho0
h = numpy.ones_like(x) * h0
cs = numpy.ones_like(x) * c0
# additional properties required for the fluid.
additional_props = [
# volume inverse or number density
'V',
# color and gradients
'color', 'scolor', 'cx', 'cy', 'cz', 'cx2', 'cy2', 'cz2',
# discretized interface normals and dirac delta
'nx', 'ny', 'nz', 'ddelta',
# interface curvature
'kappa',
# filtered velocities
'uf', 'vf', 'wf',
# transport velocities
'uhat', 'vhat', 'what', 'auhat', 'avhat', 'awhat',
# imposed accelerations on the solid wall
'ax', 'ay', 'az', 'wij',
# velocity of magnitude squared needed for TVF
'vmag2',
# variable to indicate reliable normals and normalizing
# constant
'N', 'wij_sum'
]
# get the fluid particle array
fluid = get_particle_array(
name='fluid', x=x, y=y, h=h, m=m, rho=rho, cs=cs,
additional_props=additional_props)
# set the color of the inner circle
for i in range(x.size):
if ( ((fluid.x[i]-0.5)**2 + (fluid.y[i]-0.5)**2) <= 0.25**2 ):
fluid.color[i] = 1.0
# particle volume
fluid.V[:] = 1./volume
# set additional output arrays for the fluid
fluid.add_output_arrays(['V', 'color', 'cx', 'cy', 'nx', 'ny', 'ddelta', 'p',
'kappa', 'N', 'scolor'])
print("2D Circular droplet deformation with %d fluid particles"%(
fluid.get_number_of_particles()))
return [fluid,]
def create_solver(self):
kernel = QuinticSpline(dim=2)
integrator = PECIntegrator( fluid=TransportVelocityStep() )
solver = Solver(
kernel=kernel, dim=dim, integrator=integrator,
dt=dt, tf=tf, adaptive_timestep=False, pfreq=1)
return solver
def create_equations(self):
equations = [
# We first compute the mass and number density of the fluid
# phase. This is used in all force computations henceforth. The
# number density (1/volume) is explicitly set for the solid phase
# and this isn't modified for the simulation.
Group(equations=[
SummationDensity( dest='fluid', sources=['fluid'] ),
] ),
# Given the updated number density for the fluid, we can update
# the fluid pressure. Also compute the smoothed color based on the
# color index for a particle.
Group(equations=[
StateEquation(dest='fluid', sources=None, rho0=rho0,
p0=p0, b=1.0),
SmoothedColor( dest='fluid', sources=['fluid'], smooth=True ),
] ),
#################################################################
# Begin Surface tension formulation
#################################################################
# Scale the smoothing lengths to determine the interface
# quantities.
Group(equations=[
ScaleSmoothingLength(dest='fluid', sources=None, factor=factor1)
], update_nnps=False ),
# Compute the gradient of the color function with respect to the
# new smoothing length. At the end of this Group, we will have the
# interface normals and the discretized dirac delta function for
# the fluid-fluid interface.
Group(equations=[
MorrisColorGradient(dest='fluid', sources=['fluid'], epsilon=0.01/h0),
#ColorGradientUsingNumberDensity(dest='fluid', sources=['fluid'],
# epsilon=epsilon),
#AdamiColorGradient(dest='fluid', sources=['fluid']),
],
),
# Compute the interface curvature using the modified smoothing
# length and interface normals computed in the previous Group.
Group(equations=[
InterfaceCurvatureFromNumberDensity(dest='fluid', sources=['fluid'],
with_morris_correction=True),
#AdamiReproducingDivergence(dest='fluid', sources=['fluid'],
# dim=2),
], ),
# Now rescale the smoothing length to the original value for the
# rest of the computations.
Group(equations=[
ScaleSmoothingLength(dest='fluid', sources=None, factor=factor2)
], update_nnps=False,
),
#################################################################
# End Surface tension formulation
#################################################################
# The main acceleration block
Group(
equations=[
# Gradient of pressure for the fluid phase using the
# number density formulation.
MomentumEquationPressureGradient(
dest='fluid', sources=['fluid'], pb=p0),
# Artificial viscosity for the fluid phase.
MomentumEquationViscosity(
dest='fluid', sources=['fluid'], nu=nu),
# Surface tension force for the SY11 formulation
ShadlooYildizSurfaceTensionForce(dest='fluid', sources=None, sigma=sigma),
# Artificial stress for the fluid phase
MomentumEquationArtificialStress(dest='fluid', sources=['fluid']),
], )
]
return equations
if __name__ == '__main__':
app = CircularDroplet()
app.run()
|