def _get_force_evaluator(self):
from pysph.solver.utils import load
from pysph.base.kernels import QuinticSpline
from pysph.tools.sph_evaluator import SPHEvaluator
from pysph.sph.equation import Group
from pysph.sph.wc.transport_velocity import (
SetWallVelocity, MomentumEquationPressureGradient,
SolidWallNoSlipBC, VolumeSummation, MomentumEquationViscosity)
data = load(self.output_files[0])
solid = data['arrays']['solid']
fluid = data['arrays']['fluid']
prop = [
'awhat', 'auhat', 'avhat', 'wg', 'vg', 'ug', 'V', 'uf', 'vf', 'wf',
'wij', 'vmag'
]
for p in prop:
solid.add_property(p)
fluid.add_property(p)
equations = [
Group(equations=[
SetWallVelocity(dest='fluid', sources=['solid']),
VolumeSummation(dest='fluid', sources=['fluid', 'solid']),
VolumeSummation(dest='solid', sources=['fluid', 'solid']),
],
real=False),
Group(
equations=[
# Pressure gradient terms
MomentumEquationPressureGradient(
dest='solid', sources=['fluid', 'solid'], pb=p0),
MomentumEquationViscosity(dest='solid',
sources=['fluid', 'solid'],
nu=self.nu),
SolidWallNoSlipBC(dest='solid',
sources=['fluid'],
nu=self.nu),
],
real=True),
]
sph_eval = SPHEvaluator(arrays=[solid, fluid],
equations=equations,
dim=2,
kernel=QuinticSpline(dim=2))
return sph_eval
def get_equations(self):
from pysph.sph.wc.transport_velocity import (
StateEquation, SetWallVelocity, SolidWallPressureBC,
VolumeSummation, SolidWallNoSlipBC,
MomentumEquationArtificialViscosity, ContinuitySolid)
all = self.fluids + self.solids
stage1 = []
if self.solids:
eq0 = []
for solid in self.solids:
eq0.append(SetWallVelocity(dest=solid, sources=self.fluids))
stage1.append(Group(equations=eq0, real=False))
eq1 = []
for fluid in self.fluids:
eq1.append(ContinuityEquationGTVF(dest=fluid, sources=self.fluids))
if self.solids:
eq1.append(ContinuitySolid(dest=fluid, sources=self.solids))
stage1.append(Group(equations=eq1, real=False))
eq2, stage2 = [], []
for fluid in self.fluids:
eq2.append(CorrectDensity(dest=fluid, sources=all))
stage2.append(Group(equations=eq2, real=False))
eq3 = []
for fluid in self.fluids:
eq3.append(
StateEquation(dest=fluid,
sources=None,
p0=self.pref,
rho0=self.rho0,
b=1.0))
stage2.append(Group(equations=eq3, real=False))
g2_s = []
for solid in self.solids:
g2_s.append(VolumeSummation(dest=solid, sources=all))
g2_s.append(
SolidWallPressureBC(dest=solid,
sources=self.fluids,
b=1.0,
rho0=self.rho0,
p0=self.pref,
gx=self.gx,
gy=self.gy,
gz=self.gz))
if g2_s:
stage2.append(Group(equations=g2_s, real=False))
eq4 = []
for fluid in self.fluids:
eq4.append(
MomentumEquationPressureGradient(dest=fluid,
sources=all,
pref=self.pref,
gx=self.gx,
gy=self.gy,
gz=self.gz))
if self.alpha > 0.0:
eq4.append(
MomentumEquationArtificialViscosity(dest=fluid,
sources=all,
c0=self.c0,
alpha=self.alpha))
if self.nu > 0.0:
eq4.append(
MomentumEquationViscosity(dest=fluid,
sources=all,
nu=self.nu))
if self.solids:
eq4.append(
SolidWallNoSlipBC(dest=fluid,
sources=self.solids,
nu=self.nu))
eq4.append(
MomentumEquationArtificialStress(dest=fluid,
sources=self.fluids,
dim=self.dim))
stage2.append(Group(equations=eq4, real=True))
return MultiStageEquations([stage1, stage2])
def _get_ppe(self):
from pysph.sph.wc.transport_velocity import VolumeSummation
all = self.fluids + self.solids
all_solids = self.solids
eq, stg = [], []
for fluid in self.fluids:
eq.append(SummationDensity(dest=fluid, sources=all))
stg.append(Group(equations=eq, real=False))
eq2 = []
for fluid in self.fluids:
eq2.append(VolumeSummation(dest=fluid, sources=all))
eq2.append(VelocityDivergence(dest=fluid, sources=self.fluids))
if self.solids:
eq2.append(VelocityDivergenceSolid(fluid, sources=self.solids))
stg.append(Group(equations=eq2))
solver_eqns = []
if self.has_ghosts:
ghost_eqns = Group(equations=[
UpdateGhostPressure(dest=fluid, sources=None)
for fluid in self.fluids
],
real=False)
solver_eqns = [ghost_eqns]
if all_solids:
g3 = self._get_pressure_bc()
solver_eqns.append(g3)
eq3 = []
for fluid in self.fluids:
if not fluid == 'outlet':
eq3.append(
PressureCoeffMatrixIterative(dest=fluid, sources=all))
eq3.append(
PPESolve(dest=fluid,
sources=all,
rho0=self.rho0,
rho_cutoff=self.rho_cutoff,
tolerance=self.tolerance,
omega=self.omega,
max_iterations=self.max_iterations))
eq3 = Group(equations=eq3)
solver_eqns.append(eq3)
stg.append(
Group(equations=solver_eqns,
iterate=True,
max_iterations=self.max_iterations,
min_iterations=2))
if self.has_ghosts:
ghost_eqns = Group(equations=[
UpdateGhostPressure(dest=fluid, sources=None)
for fluid in self.fluids
],
real=False)
stg.append(ghost_eqns)
return stg
def _plot_cd_vs_t(self):
from pysph.solver.utils import iter_output, load
from pysph.tools.sph_evaluator import SPHEvaluator
from pysph.sph.equation import Group
from pysph.sph.wc.transport_velocity import (SetWallVelocity,
MomentumEquationPressureGradient, SolidWallNoSlipBC,
SolidWallPressureBC, VolumeSummation)
data = load(self.output_files[0])
solid = data['arrays']['solid']
fluid = data['arrays']['fluid']
x, y = solid.x.copy(), solid.y.copy()
cx = 0.5 * L; cy = 0.5 * H
inside = np.sqrt((x-cx)**2 + (y-cy)**2) <= a
dest = solid.extract_particles(inside.nonzero()[0])
# We use the same equations for this as the simulation, except that we
# do not include the acceleration terms as these are externally
# imposed. The goal of these is to find the force of the fluid on the
# cylinder, thus, gx=0.0 is used in the following.
equations = [
Group(
equations=[
VolumeSummation(
dest='fluid', sources=['fluid', 'solid']
),
VolumeSummation(
dest='solid', sources=['fluid', 'solid']
),
], real=False),
Group(
equations=[
SetWallVelocity(dest='solid', sources=['fluid']),
], real=False),
Group(
equations=[
SolidWallPressureBC(dest='solid', sources=['fluid'],
gx=0.0, b=1.0, rho0=rho0, p0=p0),
], real=False),
Group(
equations=[
# Pressure gradient terms
MomentumEquationPressureGradient(
dest='fluid', sources=['solid'], gx=0.0, pb=pb),
SolidWallNoSlipBC(
dest='fluid', sources=['solid'], nu=nu),
], real=True),
]
sph_eval = SPHEvaluator(
arrays=[dest, fluid], equations=equations, dim=2,
kernel=QuinticSpline(dim=2)
)
t, cd = [], []
for sd, fluid in iter_output(self.output_files, 'fluid'):
fluid.remove_property('vmag2')
t.append(sd['t'])
sph_eval.update_particle_arrays([dest, fluid])
sph_eval.evaluate()
Fx = np.sum(-fluid.au*fluid.m)
cd.append(Fx/(nu*rho0*Umax))
t, cd = list(map(np.asarray, (t, cd)))
# Now plot the results.
import matplotlib
matplotlib.use('Agg')
from matplotlib import pyplot as plt
f = plt.figure()
plt.plot(t, cd)
plt.xlabel('$t$'); plt.ylabel(r'$C_D$')
fig = os.path.join(self.output_dir, "cd_vs_t.png")
plt.savefig(fig, dpi=300)
plt.close()
return t, cd
def _get_external_flow_equations(self):
from pysph.sph.basic_equations import XSPHCorrection
from pysph.sph.wc.transport_velocity import (
VolumeSummation, SolidWallNoSlipBC, SummationDensity,
MomentumEquationArtificialViscosity, MomentumEquationViscosity)
all_solids = self.solids + self.inviscid_solids
all = self.fluids + all_solids
edac_nu = self._get_edac_nu()
equations = []
group1 = []
for fluid in self.fluids:
group1.append(SummationDensity(dest=fluid, sources=all))
for solid in self.solids:
group1.extend([
SourceNumberDensity(dest=solid, sources=self.fluids),
VolumeSummation(dest=solid, sources=all),
SolidWallPressureBC(dest=solid,
sources=self.fluids,
gx=self.gx,
gy=self.gy,
gz=self.gz),
SetWallVelocity(dest=solid, sources=self.fluids),
])
if self.clamp_p:
group1.append(ClampWallPressure(dest=solid, sources=None))
for solid in self.inviscid_solids:
group1.extend([
SourceNumberDensity(dest=solid, sources=self.fluids),
NoSlipVelocityExtrapolation(dest=solid, sources=self.fluids),
VolumeSummation(dest=solid, sources=all),
SolidWallPressureBC(dest=solid,
sources=self.fluids,
gx=self.gx,
gy=self.gy,
gz=self.gz)
])
equations.append(Group(equations=group1, real=False))
group2 = []
for fluid in self.fluids:
group2.append(
MomentumEquation(dest=fluid,
sources=all,
gx=self.gx,
gy=self.gy,
gz=self.gz,
c0=self.c0,
tdamp=self.tdamp))
if self.alpha > 0.0:
group2.append(
MomentumEquationArtificialViscosity(dest=fluid,
sources=all,
alpha=self.alpha,
c0=self.c0))
if self.nu > 0.0:
group2.append(
MomentumEquationViscosity(dest=fluid,
sources=self.fluids,
nu=self.nu))
if len(self.solids) > 0 and self.nu > 0.0:
group2.append(
SolidWallNoSlipBC(dest=fluid,
sources=self.solids,
nu=self.nu))
group2.extend([
EDACEquation(dest=fluid,
sources=all,
nu=edac_nu,
cs=self.c0,
rho0=self.rho0),
XSPHCorrection(dest=fluid, sources=[fluid], eps=self.eps)
])
equations.append(Group(equations=group2))
return equations
def _get_internal_flow_equations(self):
from pysph.sph.wc.transport_velocity import (
VolumeSummation, SolidWallNoSlipBC, SummationDensity,
MomentumEquationArtificialStress,
MomentumEquationArtificialViscosity, MomentumEquationViscosity)
edac_nu = self._get_edac_nu()
iom = self.inlet_outlet_manager
fluids_with_io = self.fluids
all_solids = self.solids + self.inviscid_solids
if iom is not None:
fluids_with_io = self.fluids + iom.get_io_names()
all = fluids_with_io + all_solids
equations = []
# inlet-outlet
if iom is not None:
io_eqns = iom.get_equations(self)
for grp in io_eqns:
equations.append(grp)
group1 = []
avg_p_group = []
has_solids = len(all_solids) > 0
for fluid in fluids_with_io:
group1.append(SummationDensity(dest=fluid, sources=all))
if self.bql:
eq = ComputeAveragePressure(dest=fluid, sources=all)
if has_solids:
avg_p_group.append(eq)
else:
group1.append(eq)
for solid in self.solids:
group1.extend([
SourceNumberDensity(dest=solid, sources=fluids_with_io),
VolumeSummation(dest=solid, sources=all),
SolidWallPressureBC(dest=solid,
sources=fluids_with_io,
gx=self.gx,
gy=self.gy,
gz=self.gz),
SetWallVelocity(dest=solid, sources=fluids_with_io),
])
for solid in self.inviscid_solids:
group1.extend([
SourceNumberDensity(dest=solid, sources=fluids_with_io),
NoSlipVelocityExtrapolation(dest=solid,
sources=fluids_with_io),
NoSlipAdvVelocityExtrapolation(dest=solid,
sources=fluids_with_io),
VolumeSummation(dest=solid, sources=all),
SolidWallPressureBC(dest=solid,
sources=fluids_with_io,
gx=self.gx,
gy=self.gy,
gz=self.gz)
])
equations.append(Group(equations=group1, real=False))
# Compute average pressure *after* the wall pressure is setup.
if self.bql and has_solids:
equations.append(Group(equations=avg_p_group, real=True))
group2 = []
for fluid in self.fluids:
group2.append(
MomentumEquationPressureGradient(dest=fluid,
sources=all,
pb=self.pb,
gx=self.gx,
gy=self.gy,
gz=self.gz,
tdamp=self.tdamp))
if self.alpha > 0.0:
sources = fluids_with_io + self.solids
group2.append(
MomentumEquationArtificialViscosity(dest=fluid,
sources=sources,
alpha=self.alpha,
c0=self.c0))
if self.nu > 0.0:
group2.append(
MomentumEquationViscosity(dest=fluid,
sources=fluids_with_io,
nu=self.nu))
if len(self.solids) > 0 and self.nu > 0.0:
group2.append(
SolidWallNoSlipBC(dest=fluid,
sources=self.solids,
nu=self.nu))
group2.extend([
MomentumEquationArtificialStress(dest=fluid,
sources=fluids_with_io),
EDACEquation(dest=fluid,
sources=all,
nu=edac_nu,
cs=self.c0,
rho0=self.rho0),
])
equations.append(Group(equations=group2))
print(equations)
return equations
def get_equations(self):
from pysph.sph.equation import Group
from pysph.sph.wc.basic import TaitEOS
from pysph.sph.basic_equations import XSPHCorrection
from pysph.sph.wc.transport_velocity import (
ContinuityEquation, MomentumEquationPressureGradient,
MomentumEquationViscosity, MomentumEquationArtificialViscosity,
SolidWallPressureBC, SolidWallNoSlipBC, SetWallVelocity,
VolumeSummation)
equations = []
all = self.fluids + self.solids
g2 = []
for fluid in self.fluids:
g2.append(VolumeSummation(dest=fluid, sources=all))
g2.append(
TaitEOS(dest=fluid,
sources=None,
rho0=self.rho0,
c0=self.c0,
gamma=self.gamma,
p0=self.p0))
for solid in self.solids:
g2.append(VolumeSummation(dest=solid, sources=all))
g2.append(SetWallVelocity(dest=solid, sources=self.fluids))
equations.append(Group(equations=g2, real=False))
g3 = []
for solid in self.solids:
g3.append(
SolidWallPressureBC(dest=solid,
sources=self.fluids,
b=1.0,
rho0=self.rho0,
p0=self.B,
gx=self.gx,
gy=self.gy,
gz=self.gz))
equations.append(Group(equations=g3, real=False))
g4 = []
for fluid in self.fluids:
g4.append(ContinuityEquation(dest=fluid, sources=all))
g4.append(
MomentumEquationPressureGradient(dest=fluid,
sources=all,
pb=0.0,
gx=self.gx,
gy=self.gy,
gz=self.gz,
tdamp=self.tdamp))
if self.alpha > 0.0:
g4.append(
MomentumEquationArtificialViscosity(dest=fluid,
sources=all,
c0=self.c0,
alpha=self.alpha))
if self.nu > 0.0:
g4.append(
MomentumEquationViscosity(dest=fluid,
sources=self.fluids,
nu=self.nu))
if len(self.solids) > 0:
g4.append(
SolidWallNoSlipBC(dest=fluid,
sources=self.solids,
nu=self.nu))
g4.append(XSPHCorrection(dest=fluid, sources=[fluid]))
equations.append(Group(equations=g4))
return equations
def _get_internal_flow_equations(self):
from pysph.sph.wc.transport_velocity import (
VolumeSummation, SolidWallNoSlipBC, SummationDensity,
MomentumEquationArtificialStress,
MomentumEquationArtificialViscosity, MomentumEquationViscosity)
edac_nu = self._get_edac_nu()
all = self.fluids + self.solids
equations = []
group1 = []
avg_p_group = []
has_solids = len(self.solids) > 0
for fluid in self.fluids:
group1.append(SummationDensity(dest=fluid, sources=all))
if self.bql:
eq = ComputeAveragePressure(dest=fluid, sources=all)
if has_solids:
avg_p_group.append(eq)
else:
group1.append(eq)
for solid in self.solids:
group1.extend([
VolumeSummation(dest=solid, sources=all),
SolidWallPressureBC(dest=solid,
sources=self.fluids,
gx=self.gx,
gy=self.gy,
gz=self.gz),
SetWallVelocity(dest=solid, sources=self.fluids),
])
equations.append(Group(equations=group1, real=False))
# Compute average pressure *after* the wall pressure is setup.
if self.bql and has_solids:
equations.append(Group(equations=avg_p_group, real=True))
group2 = []
for fluid in self.fluids:
group2.append(
MomentumEquationPressureGradient(dest=fluid,
sources=all,
pb=self.pb,
gx=self.gx,
gy=self.gy,
gz=self.gz,
tdamp=self.tdamp))
if self.alpha > 0.0:
group2.append(
MomentumEquationArtificialViscosity(dest=fluid,
sources=all,
alpha=self.alpha,
c0=self.c0))
if self.nu > 0.0:
group2.append(
MomentumEquationViscosity(dest=fluid,
sources=self.fluids,
nu=self.nu))
if len(self.solids) > 0 and self.nu > 0.0:
group2.append(
SolidWallNoSlipBC(dest=fluid,
sources=self.solids,
nu=self.nu))
group2.extend([
MomentumEquationArtificialStress(dest=fluid,
sources=self.fluids),
EDACEquation(dest=fluid,
sources=all,
nu=edac_nu,
cs=self.c0,
rho0=self.rho0),
])
equations.append(Group(equations=group2))
return equations
def _get_external_flow_equations(self):
from pysph.sph.basic_equations import XSPHCorrection
from pysph.sph.wc.transport_velocity import (
VolumeSummation, SolidWallNoSlipBC, SummationDensity,
MomentumEquationArtificialViscosity,
MomentumEquationViscosity
)
iom = self.inlet_outlet_manager
fluids_with_io = self.fluids
all_solids = self.solids + self.inviscid_solids
if iom is not None:
fluids_with_io = self.fluids + iom.get_io_names()
all = fluids_with_io + all_solids
edac_nu = self._get_edac_nu()
equations = []
# inlet-outlet
if iom is not None:
io_eqns = iom.get_equations(self, self.use_tvf)
for grp in io_eqns:
equations.append(grp)
group1 = []
for fluid in fluids_with_io:
group1.append(SummationDensity(dest=fluid, sources=all))
for solid in self.solids:
group1.extend([
SourceNumberDensity(dest=solid, sources=fluids_with_io),
VolumeSummation(dest=solid, sources=all),
SolidWallPressureBC(dest=solid, sources=fluids_with_io,
gx=self.gx, gy=self.gy, gz=self.gz),
SetWallVelocity(dest=solid, sources=fluids_with_io),
])
if self.clamp_p:
group1.append(
ClampWallPressure(dest=solid, sources=None)
)
for solid in self.inviscid_solids:
group1.extend([
SourceNumberDensity(dest=solid, sources=fluids_with_io),
NoSlipVelocityExtrapolation(
dest=solid, sources=fluids_with_io),
VolumeSummation(dest=solid, sources=all),
SolidWallPressureBC(dest=solid, sources=fluids_with_io,
gx=self.gx, gy=self.gy, gz=self.gz)
])
equations.append(Group(equations=group1, real=False))
group2 = []
for fluid in self.fluids:
group2.append(
MomentumEquation(
dest=fluid, sources=all, gx=self.gx, gy=self.gy,
gz=self.gz, c0=self.c0, tdamp=self.tdamp
)
)
if self.alpha > 0.0:
sources = fluids_with_io + self.solids
group2.append(
MomentumEquationArtificialViscosity(
dest=fluid, sources=sources, alpha=self.alpha,
c0=self.c0
)
)
if self.nu > 0.0:
group2.append(
MomentumEquationViscosity(
dest=fluid, sources=fluids_with_io, nu=self.nu
)
)
if len(self.solids) > 0 and self.nu > 0.0:
group2.append(
SolidWallNoSlipBC(
dest=fluid, sources=self.solids, nu=self.nu
)
)
group2.extend([
EDACEquation(
dest=fluid, sources=all, nu=edac_nu, cs=self.c0,
rho0=self.rho0
),
XSPHCorrection(dest=fluid, sources=[fluid],
eps=self.eps)
])
equations.append(Group(equations=group2))
# inlet-outlet
if iom is not None:
io_eqns = iom.get_equations_post_compute_acceleration()
for grp in io_eqns:
equations.append(grp)
return equations