def test_slipwall_flux(actx_factory, dim, order):
"""Check for zero boundary flux.
Check for vanishing flux across the slipwall.
"""
actx = actx_factory()
wall = AdiabaticSlipBoundary()
eos = IdealSingleGas()
from pytools.convergence import EOCRecorder
eoc = EOCRecorder()
for nel_1d in [4, 8, 12]:
from meshmode.mesh.generation import generate_regular_rect_mesh
mesh = generate_regular_rect_mesh(a=(-0.5, ) * dim,
b=(0.5, ) * dim,
nelements_per_axis=(nel_1d, ) * dim)
discr = EagerDGDiscretization(actx, mesh, order=order)
nodes = thaw(actx, discr.nodes())
nhat = thaw(actx, discr.normal(BTAG_ALL))
h = 1.0 / nel_1d
from functools import partial
bnd_norm = partial(discr.norm, p=np.inf, dd=BTAG_ALL)
logger.info(f"Number of {dim}d elems: {mesh.nelements}")
# for velocities in each direction
err_max = 0.0
for vdir in range(dim):
vel = np.zeros(shape=(dim, ))
# for velocity directions +1, and -1
for parity in [1.0, -1.0]:
vel[vdir] = parity
from mirgecom.initializers import Uniform
initializer = Uniform(dim=dim, velocity=vel)
uniform_state = initializer(nodes)
bnd_pair = wall.boundary_pair(discr,
btag=BTAG_ALL,
eos=eos,
cv=uniform_state)
# Check the total velocity component normal
# to each surface. It should be zero. The
# numerical fluxes cannot be zero.
avg_state = 0.5 * (bnd_pair.int + bnd_pair.ext)
err_max = max(err_max,
bnd_norm(np.dot(avg_state.momentum, nhat)))
from mirgecom.euler import _facial_flux
bnd_flux = _facial_flux(discr,
eos,
cv_tpair=bnd_pair,
local=True)
err_max = max(err_max, bnd_norm(bnd_flux.mass),
bnd_norm(bnd_flux.energy))
eoc.add_data_point(h, err_max)
message = (f"EOC:\n{eoc}")
logger.info(message)
assert (eoc.order_estimate() >= order - 0.5 or eoc.max_error() < 1e-12)
def test_slipwall_identity(actx_factory, dim):
"""Identity test - check for the expected boundary solution.
Checks that the slipwall implements the expected boundary solution:
rho_plus = rho_minus
v_plus = v_minus - 2 * (n_hat . v_minus) * n_hat
mom_plus = rho_plus * v_plus
E_plus = E_minus
"""
actx = actx_factory()
nel_1d = 4
from meshmode.mesh.generation import generate_regular_rect_mesh
mesh = generate_regular_rect_mesh(a=(-0.5, ) * dim,
b=(0.5, ) * dim,
nelements_per_axis=(nel_1d, ) * dim)
order = 3
discr = EagerDGDiscretization(actx, mesh, order=order)
nodes = thaw(actx, discr.nodes())
eos = IdealSingleGas()
orig = np.zeros(shape=(dim, ))
nhat = thaw(actx, discr.normal(BTAG_ALL))
logger.info(f"Number of {dim}d elems: {mesh.nelements}")
# for velocity going along each direction
for vdir in range(dim):
vel = np.zeros(shape=(dim, ))
# for velocity directions +1, and -1
for parity in [1.0, -1.0]:
vel[vdir] = parity # Check incoming normal
initializer = Lump(dim=dim, center=orig, velocity=vel, rhoamp=0.0)
wall = AdiabaticSlipBoundary()
uniform_state = initializer(nodes)
from functools import partial
bnd_norm = partial(discr.norm, p=np.inf, dd=BTAG_ALL)
bnd_pair = wall.boundary_pair(discr,
btag=BTAG_ALL,
eos=eos,
cv=uniform_state)
# check that mass and energy are preserved
mass_resid = bnd_pair.int.mass - bnd_pair.ext.mass
mass_err = bnd_norm(mass_resid)
assert mass_err == 0.0
energy_resid = bnd_pair.int.energy - bnd_pair.ext.energy
energy_err = bnd_norm(energy_resid)
assert energy_err == 0.0
# check that exterior momentum term is mom_interior - 2 * mom_normal
mom_norm_comp = np.dot(bnd_pair.int.momentum, nhat)
mom_norm = nhat * mom_norm_comp
expected_mom_ext = bnd_pair.int.momentum - 2.0 * mom_norm
mom_resid = bnd_pair.ext.momentum - expected_mom_ext
mom_err = bnd_norm(mom_resid)
assert mom_err == 0.0
def test_facial_flux(actx_factory, nspecies, order, dim):
"""Check the flux across element faces.
The flux is checked by prescribing states (q) with known fluxes. Only uniform
states are tested currently - ensuring that the Lax-Friedrichs flux terms which
are proportional to jumps in state data vanish.
Since the returned fluxes use state data which has been interpolated
to-and-from the element faces, this test is grid-dependent.
"""
actx = actx_factory()
tolerance = 1e-14
p0 = 1.0
from meshmode.mesh.generation import generate_regular_rect_mesh
from pytools.convergence import EOCRecorder
eoc_rec0 = EOCRecorder()
eoc_rec1 = EOCRecorder()
for nel_1d in [4, 8, 12]:
mesh = generate_regular_rect_mesh(a=(-0.5, ) * dim,
b=(0.5, ) * dim,
nelements_per_axis=(nel_1d, ) * dim)
logger.info(f"Number of elements: {mesh.nelements}")
discr = EagerDGDiscretization(actx, mesh, order=order)
zeros = discr.zeros(actx)
ones = zeros + 1.0
mass_input = discr.zeros(actx) + 1.0
energy_input = discr.zeros(actx) + 2.5
mom_input = flat_obj_array(
[discr.zeros(actx) for i in range(discr.dim)])
mass_frac_input = flat_obj_array(
[ones / ((i + 1) * 10) for i in range(nspecies)])
species_mass_input = mass_input * mass_frac_input
cv = make_conserved(dim,
mass=mass_input,
energy=energy_input,
momentum=mom_input,
species_mass=species_mass_input)
from grudge.trace_pair import interior_trace_pairs
cv_interior_pairs = interior_trace_pairs(discr, cv)
# Check the boundary facial fluxes as called on an interior boundary
# eos = IdealSingleGas()
from mirgecom.gas_model import (GasModel, make_fluid_state)
gas_model = GasModel(eos=IdealSingleGas())
from mirgecom.gas_model import make_fluid_state_trace_pairs
state_tpairs = make_fluid_state_trace_pairs(cv_interior_pairs,
gas_model)
interior_state_pair = state_tpairs[0]
from mirgecom.inviscid import inviscid_facial_flux
interior_face_flux = \
inviscid_facial_flux(discr, state_tpair=interior_state_pair)
def inf_norm(data):
if len(data) > 0:
return actx.to_numpy(discr.norm(data, np.inf, dd="all_faces"))
else:
return 0.0
assert inf_norm(interior_face_flux.mass) < tolerance
assert inf_norm(interior_face_flux.energy) < tolerance
assert inf_norm(interior_face_flux.species_mass) < tolerance
# The expected pressure is 1.0 (by design). And the flux diagonal is
# [rhov_x*v_x + p] (etc) since we have zero velocities it's just p.
#
# The off-diagonals are zero. We get a {ndim}-vector for each
# dimension, the flux for the x-component of momentum (for example) is:
# f_momx = < 1.0, 0 , 0> , then we return f_momx .dot. normal, which
# can introduce negative values.
#
# (Explanation courtesy of Mike Campbell,
# https://github.com/illinois-ceesd/mirgecom/pull/44#discussion_r463304292)
nhat = thaw(actx, discr.normal("int_faces"))
mom_flux_exact = discr.project("int_faces", "all_faces", p0 * nhat)
print(f"{mom_flux_exact=}")
print(f"{interior_face_flux.momentum=}")
momerr = inf_norm(interior_face_flux.momentum - mom_flux_exact)
assert momerr < tolerance
eoc_rec0.add_data_point(1.0 / nel_1d, momerr)
# Check the boundary facial fluxes as called on a domain boundary
dir_mass = discr.project("vol", BTAG_ALL, mass_input)
dir_e = discr.project("vol", BTAG_ALL, energy_input)
dir_mom = discr.project("vol", BTAG_ALL, mom_input)
dir_mf = discr.project("vol", BTAG_ALL, species_mass_input)
dir_bc = make_conserved(dim,
mass=dir_mass,
energy=dir_e,
momentum=dir_mom,
species_mass=dir_mf)
dir_bval = make_conserved(dim,
mass=dir_mass,
energy=dir_e,
momentum=dir_mom,
species_mass=dir_mf)
state_tpair = TracePair(BTAG_ALL,
interior=make_fluid_state(dir_bval, gas_model),
exterior=make_fluid_state(dir_bc, gas_model))
boundary_flux = inviscid_facial_flux(discr, state_tpair=state_tpair)
assert inf_norm(boundary_flux.mass) < tolerance
assert inf_norm(boundary_flux.energy) < tolerance
assert inf_norm(boundary_flux.species_mass) < tolerance
nhat = thaw(actx, discr.normal(BTAG_ALL))
mom_flux_exact = discr.project(BTAG_ALL, "all_faces", p0 * nhat)
momerr = inf_norm(boundary_flux.momentum - mom_flux_exact)
assert momerr < tolerance
eoc_rec1.add_data_point(1.0 / nel_1d, momerr)
logger.info(f"standalone Errors:\n{eoc_rec0}"
f"boundary Errors:\n{eoc_rec1}")
assert (eoc_rec0.order_estimate() >= order - 0.5
or eoc_rec0.max_error() < 1e-9)
assert (eoc_rec1.order_estimate() >= order - 0.5
or eoc_rec1.max_error() < 1e-9)