def test_initialization(dtype_device, use_jacobi):
dtype, device = dtype_device
lattice = Lattice(D2Q9, device, dtype)
flow = TaylorGreenVortex2D(resolution=24,
reynolds_number=10,
mach_number=0.05,
lattice=lattice)
collision = BGKCollision(lattice, tau=flow.units.relaxation_parameter_lu)
streaming = StandardStreaming(lattice)
simulation = Simulation(flow=flow,
lattice=lattice,
collision=collision,
streaming=streaming)
# set initial pressure to 0 everywhere
p, u = flow.initial_solution(flow.grid)
u0 = lattice.convert_to_tensor(flow.units.convert_velocity_to_lu(u))
rho0 = lattice.convert_to_tensor(np.ones_like(u0[0, ...].cpu()))
simulation.f = lattice.equilibrium(rho0, u0)
if use_jacobi:
simulation.initialize_pressure(1000, 1e-6)
num_iterations = 0
else:
num_iterations = simulation.initialize(500, 1e-3)
piter = lattice.convert_to_numpy(
flow.units.convert_density_lu_to_pressure_pu(lattice.rho(
simulation.f)))
# assert that pressure is converged up to 0.05 (max p
assert piter == pytest.approx(p, rel=0.0, abs=5e-2)
assert num_iterations < 500
def test_equilibrium_pressure_outlet(dtype_device):
dtype, device = dtype_device
lattice = Lattice(D2Q9, dtype=dtype, device=device)
class MyObstacle(Obstacle2D):
@property
def boundaries(self, *args):
x, y = self.grid
return [
EquilibriumBoundaryPU(
np.abs(x) < 1e-6, self.units.lattice, self.units,
np.array([self.units.characteristic_velocity_pu, 0])),
EquilibriumOutletP(self.units.lattice, [0, -1]),
EquilibriumOutletP(self.units.lattice, [0, 1]),
EquilibriumOutletP(self.units.lattice, [1, 0]),
BounceBackBoundary(self.mask, self.units.lattice)
]
flow = MyObstacle(30,
30,
reynolds_number=10,
mach_number=0.1,
lattice=lattice,
char_length_lu=10)
mask = np.zeros_like(flow.grid[0], dtype=np.bool)
mask[10:20, 10:20] = 1
flow.mask = mask
simulation = Simulation(
flow, lattice,
RegularizedCollision(lattice, flow.units.relaxation_parameter_lu),
StandardStreaming(lattice))
simulation.step(20)
rho = lattice.rho(simulation.f)
u = lattice.u(simulation.f)
feq = lattice.equilibrium(torch.ones_like(rho), u)
p = flow.units.convert_density_lu_to_pressure_pu(rho)
zeros = torch.zeros_like(p[0, -1, :])
assert torch.allclose(zeros, p[:, -1, :], rtol=0, atol=1e-4)
assert torch.allclose(zeros, p[:, :, 0], rtol=0, atol=1e-4)
assert torch.allclose(zeros, p[:, :, -1], rtol=0, atol=1e-4)
assert torch.allclose(feq[:, -1, 1:-1], feq[:, -2, 1:-1])