def hydro_grid_in_potential_well(mass=1 | units.MSun, length=100 | units.AU):
converter = nbody_system.nbody_to_si(mass, length)
# calculate density in field based on solar wind
# gives a very low number
molar_mass_hydrogen_proton = 1 | units.g / units.mol
density_hydrogen_in_stellar_wind = 10 | 1 / units.cm**3
particles_per_mol = 6.022e23 | 1 / units.mol
density_hydrogen_in_stellar_wind_in_moles = (
density_hydrogen_in_stellar_wind
/ particles_per_mol
)
density_gas = 100 * (
density_hydrogen_in_stellar_wind_in_moles
* molar_mass_hydrogen_proton
).as_quantity_in(units.MSun / units.AU**3)
# override with higher number for plotting
density_gas = 1e-3 | units.MSun / units.AU**3
instance = Athena(converter)
instance.initialize_code()
instance.parameters.nx = 50
instance.parameters.ny = 50
instance.parameters.nz = 1
instance.parameters.length_x = length
instance.parameters.length_y = length
instance.parameters.length_z = length
instance.parameters.x_boundary_conditions = ("periodic", "periodic")
instance.parameters.y_boundary_conditions = ("periodic", "periodic")
instance.parameters.z_boundary_conditions = ("outflow", "outflow")
# instance.stopping_conditions.number_of_steps_detection.enable()
instance.set_has_external_gravitational_potential(1)
instance.commit_parameters()
grid_in_memory = instance.grid.copy()
grid_in_memory.rho = density_gas
pressure = 1 | units.Pa
grid_in_memory.energy = pressure / (instance.parameters.gamma - 1)
channel = grid_in_memory.new_channel_to(instance.grid)
channel.copy()
instance.initialize_grid()
particle = Particle(
mass=mass,
position=length * [0.5, 0.5, 0.5],
velocity=[0.0, 0.0, 0.0] | units.kms
)
gravity = Hermite(converter)
dx = (grid_in_memory.x[1][0][0] - grid_in_memory.x[0]
[0][0]).as_quantity_in(units.AU)
gravity.parameters.epsilon_squared = dx**2
gravity.particles.add_particle(particle)
potential = gravity.get_potential_at_point(
0 * instance.potential_grid.x.flatten(),
instance.potential_grid.x.flatten(),
instance.potential_grid.y.flatten(),
instance.potential_grid.z.flatten()
)
potential = potential.reshape(instance.potential_grid.x.shape)
instance.potential_grid.potential = potential
instance.evolve_model(100 | units.yr)
print(instance.get_timestep().value_in(units.yr))
value_to_plot = instance.grid.rho[:, :, 0].value_in(
units.MSun / units.AU**3)
# value_to_plot = potential[...,...,0].value_in(potential.unit)
plot_grid(value_to_plot)
def hydro_grid_in_potential_well(mass=1 | units.MSun, length=100 | units.AU):
converter = nbody_system.nbody_to_si(mass, length)
# calculate density in field based on solar wind
# gives a very low number
molar_mass_hydrogen_proton = 1 | units.g / units.mol
density_hydrogen_in_stellar_wind = 10 | 1 / units.cm**3
particles_per_mol = 6.022e23 | 1 / units.mol
density_hydrogen_in_stellar_wind_in_moles = (
density_hydrogen_in_stellar_wind
/ particles_per_mol
)
density_gas = 100 * (
density_hydrogen_in_stellar_wind_in_moles
* molar_mass_hydrogen_proton
).as_quantity_in(units.MSun / units.AU**3)
# override with higher number for plotting
density_gas = 1e-3 | units.MSun / units.AU**3
instance = Athena(converter)
instance.initialize_code()
instance.parameters.nx = 50
instance.parameters.ny = 50
instance.parameters.nz = 1
instance.parameters.length_x = length
instance.parameters.length_y = length
instance.parameters.length_z = length
instance.parameters.x_boundary_conditions = ("periodic", "periodic")
instance.parameters.y_boundary_conditions = ("periodic", "periodic")
instance.parameters.z_boundary_conditions = ("outflow", "outflow")
# instance.stopping_conditions.number_of_steps_detection.enable()
instance.set_has_external_gravitational_potential(1)
instance.commit_parameters()
grid_in_memory = instance.grid.copy()
grid_in_memory.rho = density_gas
pressure = 1 | units.Pa
grid_in_memory.energy = pressure / (instance.parameters.gamma - 1)
channel = grid_in_memory.new_channel_to(instance.grid)
channel.copy()
instance.initialize_grid()
particle = Particle(
mass=mass,
position=length * [0.5, 0.5, 0.5],
velocity=[0.0, 0.0, 0.0] | units.kms
)
gravity = Hermite(converter)
dx = (grid_in_memory.x[1][0][0] - grid_in_memory.x[0]
[0][0]).as_quantity_in(units.AU)
gravity.parameters.epsilon_squared = dx**2
gravity.particles.add_particle(particle)
potential = gravity.get_potential_at_point(
0 * instance.potential_grid.x.flatten(),
instance.potential_grid.x.flatten(),
instance.potential_grid.y.flatten(),
instance.potential_grid.z.flatten()
)
potential = potential.reshape(instance.potential_grid.x.shape)
instance.potential_grid.potential = potential
instance.evolve_model(100 | units.yr)
print(instance.get_timestep().value_in(units.yr))
value_to_plot = instance.grid.rho[:, :, 0].value_in(
units.MSun / units.AU**3)
# value_to_plot = potential[...,...,0].value_in(potential.unit)
plot_grid(value_to_plot)
hydro_code = Athena(unit_converter=converter,
number_of_workers=2) #,redirection='none')
hydro_code.initialize_code()
hydro_code.parameters.gamma = 1.001
hydro_code.parameters.courant_number = 0.3
hydro_code.parameters.mesh_size = (number_of_grid_points,
number_of_grid_points,
number_of_grid_points)
hydro_code.parameters.length_x = 1 | length
hydro_code.parameters.length_y = 1 | length
hydro_code.parameters.length_z = 1 | length
hydro_code.parameters.x_boundary_conditions = ("periodic", "periodic")
hydro_code.parameters.y_boundary_conditions = ("periodic", "periodic")
hydro_code.parameters.z_boundary_conditions = ("periodic", "periodic")
hydro_code.commit_parameters()
set_initial_conditions(hydro_code, converter)
times = t_end * range(n_steps) / n_steps
for i, t in enumerate(t_end * range(n_steps) / float(n_steps)):
print t.in_(units.Myr), hydro_code.model_time.in_(units.Myr)
print "Hydro evolve 1"
hydro_code.evolve_model(t + dt / 2.0)
print "Cooling"
hydro_code.grid.energy = evolve_internal_energy(
hydro_code.grid.energy / hydro_code.grid.rho, dt,
hydro_code.grid.rho / global_mu) * hydro_code.grid.rho
print(global_mu / constants.kB *
(hydro_code.grid.energy / hydro_code.grid.rho).amin()).in_(
units.K),
