verbose (1: diagnostic output)
scale_function
Standard settings:
constant 1.0
monomial 1.0 1.0
monomial 2.0 1.0
table1d n # number of points in table x1 A1 x2 A2 ... xn Anwhere (x,A) are (position,area) pairs.
number For each: definition
Materials are of type mat_type
in Ariadne.
number For each: position velocity number_of_cells_using_node For each: index
number For each: density specific_internal_energy fraction_reacted index_of_material number_of_nodes_defining_cell For each: index
number For each: node_location velocity_function_of_time(See note below on defining locations.)
number For each: cell_location pressure_function_of_time(See note below on defining locations.)
number For each: position pressure_function_of_velocity
The `pressure' is a force (vector) per unit area.
number For each: cell_location velocity material_name material_state amplitude
The amplitude is a function of time, used to scale the velocity and state. The material name is needed to determine the tye of state to read in; this cannot be determined from the cell index because of the structure of the program so this degree of redundancy is needed. (See note below on defining locations.)
number For each: cell_location_1 cell_location_2 heating_rate
The heating rate is a function of time. It defines the heat energy per time applied to each cell in the range. (See note below on defining locations.)
number For each: cell_location time
At a control point, the time is for the detonation wave to pass the cell centre. (See note below on defining locations.)
number For each: node_location location_of_nearest_node_inside_explosive(See note below on defining locations.)
sound_speed divergence artificial_viscosity evolution_rate detonation
The timestep safety factors are used to ensure that the numerical scheme is stable, accurate and convergent. Each physical process has an associated timescale. The time increments taken during a simulation must be small enough that each process can be represented properly. On the other hand, unnecessarily small time steps require more computer time, and can make the result less accurate because of numerical rounding and diffusion processes.
If all the safety factors are set to 1 then the numerical scheme would take its best guess at a timestep. This assumes linear physics, which is not really the case. For non-linear processes it is common to adopt a safety factor ~0.7 say. For stiffer problems, 0.4 seems more reliable.
The timescales are:
In many cases evolution rates are so fast in comparison with macroscopic hydrodynamics that it is better to subcycle the evolution and not permit it to influence the hydrodynamic timestep. If subcycling is used, the safety factor can be set to a large number such as 1010.
quadratic linear qmode q_evolve_cut maximum q/p for evolution to proceed
Notes:
order
Permissible values:
flag (0: off, 1: on) psi_store_u (value of psi field at which to store local particle velocity) trigger_delay (delay between triggering of WBL/DSD initiation point and actual value used for the new control point) psi_trigger_disable (value of psi at which to disable WBL/DSD triggering) psi_wake (value of psi at which to start full detonics) psi_dead (value of psi at which to ignore detonics)
initial_timestep growth_factor minimum_timestep action maximum_timestep action
"action" can be "set" or "abort". The action is taken if the calculated timestep falls outwith the corresponding limit.
approximate_zero approximate_infinity
cc_option
Permitted values:
raw no action (will probably fail if imaginary speeds are calculated) ignore don't use imaginary values in calculating time step abs take (sq. root of) absolute value of square of sound speed
start_time final_time maximum_timesteps
number_of_conditions For each: position_in_initial_mesh (as a cell location) parameter (pressure / temperature) relation (above / below) test_value(See note below on defining locations.)
number_of_steps_between_outputs output_file_stem first_output_index time_interval_between_node_plot_dumps node_plot_file_stem first_output_index time_interval_between_cell_plot_dumps cell_plot_file_stem first_output_index name_of_shock_location_file artificial_viscosity_cutoff number_of_Lagrangian_sensors For each: initial_position filename type number_of_extremum_sensors For each: cell_location_end1 cell_location_end2 sense (maximum / minimum) parameter (pressure/temperature/velocity) filename
"type" is "node" or "cell". Position is specified as a location (see note below on defining locations).
The artificial viscosity cutoff is used to select the level at which a compression wave is taken to be a shock. The cell centre closest to each Lagrangian sensor is found, and the state in this cell written to the specified file at each time step.
index index_valueIndices are base zero, following the C array convention.
position ordinate
sense endwhere
end
may be left
or right
.
# dump at time = ... (geometry information)
The geometry information consists of node and cell states, followed by the boundary conditions. It can be used to restart the calculation by inserting the rest of the control data round about.
# node plot at time = .... # parameters: pos, vel, stress, T, csq, q, psi, u0, d For each node: position velocity stress (6 components) T c2 q psi u0 D
Cell plot:
# cell plot at time = .... # parameters: pos, vel, stress, T, csq, q, psi, u0, d, material, state For each node: position velocity stress (6 components) T c2 q psi u0 D material state
For node plots, apart from position and velocity, quantities are averaged from the cells containing the node. For cell plots, position and velocity are averaged from nodes defining the cell.
The graphics dumps are suitable for display using Gnuplot.