imod.wq.TimeDiscretization#

class imod.wq.TimeDiscretization(timestep_duration, n_timesteps=1, transient=True, timestep_multiplier=1.0, max_n_transport_timestep=50000, transport_timestep_multiplier=None, transport_initial_timestep=0.0)[source]#

Time discretisation package class.

Parameters:

  • timestep_duration (float) – is the length of the current stress period (PERLEN). If the flow solution is transient, timestep_duration specified here must be equal to that specified for the flow model. If the flow solution is steady-state, timestep_duration can be set to any desired length.

  • n_timesteps (int, optional) – is the number of time steps for the transient flow solution in the current stress period (NSTP). If the flow solution is steady-state, n_timestep=1. Default value is 1.

  • transient (bool, optional) – Flag indicating wether the flow simulation is transient (True) or False (Steady State). Default is True.

  • timestep_multiplier (float, optional) – is the multiplier for the length of successive time steps used in the transient flow solution (TSMULT); it is used only if n_timesteps>1. timestep_multiplier>0, the length of each flow time step within the current stress period is calculated using the geometric progression as in MODFLOW. Note that both n_timesteps and timestep_multiplier specified here must be identical to those specified in the flow model if the flow model is transient. timestep_multiplier ≤ 0, the length of each flow time step within the current stress period is read from the record TSLNGH. This option is needed in case the length of time steps for the flow solution is not based on a geometric progression in a flow model, unlike MODFLOW. Default is 1.0.

  • max_n_transport_timestep (int, optional) – is the maximum number of transport steps allowed within one time step of the flow solution (mxstrn). If the number of transport steps within a flow time step exceeds max_n_transport_timestep, the simulation is terminated. Default is 50_000.

  • transport_timestep_multiplier (float or {"None"}, optional) – is the multiplier for successive transport steps within a flow time step (TTSMULT). If the Generalized Conjugate Gradient (GCG) solver is used and the solution option for the advection term is the standard finite difference method. A value between 1.0 and 2.0 is generally adequate. If the GCG package is not used, the transport solution is solved explicitly as in the original MT3D code, and transport_timestep_multiplier is always set to 1.0 regardless of the user-specified input. Note that for the particle tracking based solution options and the 3rd-order TVD scheme, transport_timestep_multiplier does not apply. Default is {“None”}.

  • transport_initial_timestep (int, optional) – is the user-specified transport stepsize within each time step of the flow solution (DT0). transport_initial_timestep is interpreted differently depending on whether the solution option chosen is explicit or implicit: For explicit solutions (i.e., the GCG solver is not used), the program will always calculate a maximum transport stepsize which meets the various stability criteria. Setting transport_initial_timestep to zero causes the model calculated transport stepsize to be used in the simulation. However, the model-calculated transport_initial_timestep may not always be optimal. In this situation, transport_initial_timestep should be adjusted to find a value that leads to the best results. If transport_initial_timestep is given a value greater than the model-calculated stepsize, the model-calculated stepsize, instead of the user-specified value, will be used in the simulation. For implicit solutions (i.e., the GCG solver is used), transport_initial_timestep is the initial transport stepsize. If it is specified as zero, the model-calculated value of transport_initial_timestep, based on the user-specified Courant number in the Advection Package, will be used. The subsequent transport stepsize may increase or remain constant depending on the userspecified transport stepsize multiplier transport_timestep_multiplier and the solution scheme for the advection term. Default is 0.

__init__(timestep_duration, n_timesteps=1, transient=True, timestep_multiplier=1.0, max_n_transport_timestep=50000, transport_timestep_multiplier=None, transport_initial_timestep=0.0)[source]#

Methods

__init__(timestep_duration[, n_timesteps, ...])

from_file(path, **kwargs)

Loads an imod-wq package from a file (currently only netcdf and zarr are supported).

isel()

save(directory)

sel()