transient_controls#

class ansys.fluent.core.solver.tui_231.main_menu.solve.set.transient_controls(path, service)#

Bases: TUIMenu

Enters the transient controls menu, which allows you to define settings related to time advancement for transient flow calculations.

Methods:

`cfl_based_time_stepping`(args, *kwargs)	Allows you to specify that an adaptive time stepping method is used in which the time step gets modified by ANSYS Fluent as the calculation proceeds such that the Courant–Friedrichs–Lewy (CFL) condition is satisfied, using the specified Courant number.
`cfl_based_time_stepping_advanced_options`(...)	Set CFL-based adaptive time-stepping advanced parameters.
`duration_specification_method`(args, *kwargs)	Sets the method by which you will specify the duration of the calculation.
`error_based_time_stepping`(args, *kwargs)	Allows you to specify that an adaptive time stepping method is used in which the time step gets modified by ANSYS Fluent based on the specified truncation error tolerance.
`extrapolate_eqn_vars`(args, *kwargs)	Enters the extrapolation menu.
`extrapolate_vars`(args, *kwargs)	Applies a predictor algorithm for computing initial conditions at time step n+1.
`fixed_periodic`(args, *kwargs)	Allows you to specify that a fixed time stepping method is used in which a specified period or frequency is the basis for determining the time step size and number of time steps.
`fixed_user_specified`(args, *kwargs)	Allows you to specify that a fixed time stepping method is used in which you directly specify the time step size and number of time steps.
`incremental_time`(args, *kwargs)	Sets the amount of incremental (that is, additional) time to run the simulation, regardless of how much time has already been run in previous calculations.
`max_flow_time`(args, *kwargs)	Sets the maximum flow time.
`max_iterations_per_time_step`(args, *kwargs)	Sets the number of time steps for a transient simulation.
`multiphase_specific_time_stepping`(*args, ...)	Allows you to specify that an adaptive time stepping method is used in which the time step gets modified by ANSYS Fluent based on the convective time scale (global Courant number): the time-step-size calculation depends on the mesh density and velocity in interfacial cells.
`number_of_time_steps`(args, *kwargs)	Sets the number of time steps for a transient simulation without starting the calculation.
`predict_next_time`(args, *kwargs)	Applies a predictor algorithm for computing the next time step.
`rotating_mesh_flow_predictor`(args, *kwargs)	Enables / disables an option that allows for better prediction of the flow field in rotating fluid zones at every time step, in order to speed up the calculation.
`solid_time_step_size`(args, *kwargs)	Allows you to specify that the time step size used for solid zones is independent from that used for fluid zones.
`solution_status`(args, *kwargs)	Allows you to open theSimulation Status dialog box, which reports details about the simulation.
`specified_time_step`(args, *kwargs)	Specifies whether to define the transient advancement either directly by entering a time step size / period / frequency (using the text commands available in thesolve/set/transient-controls menu) or indirectly by entering a Courant number value (using the solve/set/courant-number text command).
`time_step_size`(args, *kwargs)	Sets the magnitude of the (physical) time step .
`time_step_size_for_acoustic_export`(*args, ...)	Specifies the time interval for acoustic data sampling.
`total_number_of_time_steps`(args, *kwargs)	Sets the total number of time steps that the simulation will run (which includes any time steps that have already been run in previous calculations).
`total_time`(args, *kwargs)	Sets the total amount of time that the simulation will be run (which includes any time that has already been run in previous calculations).
`udf_based_time_stepping`(args, *kwargs)	Allows you to specify that the time step size is defined by a user-defined function (UDF) that uses theDEFINE_DELTAT macro.
`undo_timestep`(args, *kwargs)	When enabled, if the truncation error within a time step exceeds the specified tolerance Fluent will automatically undo the current calculation and make another attempt with the time step reduced by 1/2.

Classes:

multiphase_specific_time_constraints(path, ...)

Enters the menu for setting multiphase-specific time constraints.

cfl_based_time_stepping(*args, **kwargs)#: Allows you to specify that an adaptive time stepping method is used in which the time step gets modified by ANSYS Fluent as the calculation proceeds such that the Courant–Friedrichs–Lewy (CFL) condition is satisfied, using the specified Courant number.

cfl_based_time_stepping_advanced_options(*args, **kwargs)#: Set CFL-based adaptive time-stepping advanced parameters.

duration_specification_method(*args, **kwargs)#: Sets the method by which you will specify the duration of the calculation. The duration can be defined by the total time, the total number of time steps, the incremental time, or the number of incremental time steps. In this context, “total” indicates that Fluent will consider the amount of time / steps that have already been solved and stop appropriately, whereas “incremental” indicates that the solution will proceed for a specified amount of time / steps regardless of what has previously been calculated. This text command is only available when the time stepping is adaptive or based on a user-defined function.

error_based_time_stepping(*args, **kwargs)#: Allows you to specify that an adaptive time stepping method is used in which the time step gets modified by ANSYS Fluent based on the specified truncation error tolerance.

extrapolate_eqn_vars(*args, **kwargs)#: Enters the extrapolation menu.

extrapolate_vars(*args, **kwargs)#: Applies a predictor algorithm for computing initial conditions at time step n+1. The predictor algorithm is a computation that sets a better initial condition for the time step.

fixed_periodic(*args, **kwargs)#: Allows you to specify that a fixed time stepping method is used in which a specified period or frequency is the basis for determining the time step size and number of time steps.

fixed_user_specified(*args, **kwargs)#: Allows you to specify that a fixed time stepping method is used in which you directly specify the time step size and number of time steps.

incremental_time(*args, **kwargs)#: Sets the amount of incremental (that is, additional) time to run the simulation, regardless of how much time has already been run in previous calculations. This text command is only available when the solve/set/transient-controls/duration-specification-method is set to3.

max_flow_time(*args, **kwargs)#: Sets the maximum flow time.

max_iterations_per_time_step(*args, **kwargs)#: Sets the number of time steps for a transient simulation. This option is available when automatic initialization and case modification is enabled.

class multiphase_specific_time_constraints(path, service)#

Bases: TUIMenu

Enters the menu for setting multiphase-specific time constraints.

Methods:

`moving_mesh_cfl_constraint`(args, *kwargs)	Enable time step size constraints based on moving mesh courant number.
`physics_based_constraint`(args, *kwargs)	Enables/disables the physics-driven time-step constraints.
`verbosity`(args, *kwargs)	When enabled, various time scales (depending on the selection) are printed to the console window at every time step.

Classes:

time_scale_options(path, service)

Enters the menu for choosing the time-scale options.

moving_mesh_cfl_constraint(*args, **kwargs)#: Enable time step size constraints based on moving mesh courant number.

physics_based_constraint(*args, **kwargs)#: Enables/disables the physics-driven time-step constraints.

class time_scale_options(path, service)#

Bases: TUIMenu

Enters the menu for choosing the time-scale options. This menu becomes available after you enable the physics-driven time-step constraints using the solve/set/transient-controls/multiphase-specific-time-constraints/physics-based-constraint? text command.

Methods:

`acoustic_scale`(args, *kwargs)	Allows you to Include the acoustic time scale.
`gravity_scale`(args, *kwargs)	Allows you to Include the gravitational time scale.
`surface_tension_scale`(args, *kwargs)	Allows you to Include the surface-tension-driven time scale.
`viscous_scale`(args, *kwargs)	Allows you to Include the viscous time scale.

acoustic_scale(*args, **kwargs)#: Allows you to Include the acoustic time scale. This option is available only for compressible flows.

gravity_scale(*args, **kwargs)#: Allows you to Include the gravitational time scale. This option is available only if gravity is enabled.

surface_tension_scale(*args, **kwargs)#: Allows you to Include the surface-tension-driven time scale. This option is available only if the surface tension force modeling is enabled.

viscous_scale(*args, **kwargs)#: Allows you to Include the viscous time scale. This option is disabled by default. This command is not available with inviscid flows.

verbosity(*args, **kwargs)#: When enabled, various time scales (depending on the selection) are printed to the console window at every time step. This text command is available with the moving mesh CFL constraint and with the physics-based constraint.

multiphase_specific_time_stepping(*args, **kwargs)#: Allows you to specify that an adaptive time stepping method is used in which the time step gets modified by ANSYS Fluent based on the convective time scale (global Courant number): the time-step-size calculation depends on the mesh density and velocity in interfacial cells. This method is available for all multiphase models using the implicit or explicit volume fraction formulation, except for the wet steam model.

number_of_time_steps(*args, **kwargs)#: Sets the number of time steps for a transient simulation without starting the calculation.

predict_next_time(*args, **kwargs)#: Applies a predictor algorithm for computing the next time step. The predictor algorithm is a computation that sets a better initial condition for the time step. It uses the rate of change between the prediction and the correction as an indicator for whether the next time step should be larger, smaller, or the same as the current one.

rotating_mesh_flow_predictor(*args, **kwargs)#: Enables / disables an option that allows for better prediction of the flow field in rotating fluid zones at every time step, in order to speed up the calculation. This text command is only available for transient simulations.

solid_time_step_size(*args, **kwargs)#: Allows you to specify that the time step size used for solid zones is independent from that used for fluid zones. This text command is only available when both a solid zone exists and energy is enabled.

solution_status(*args, **kwargs)#: Allows you to open theSimulation Status dialog box, which reports details about the simulation.

specified_time_step(*args, **kwargs)#: Specifies whether to define the transient advancement either directly by entering a time step size / period / frequency (using the text commands available in thesolve/set/transient-controls menu) or indirectly by entering a Courant number value (using the solve/set/courant-number text command). This text command is only available for the density-based solver when both the explicit formulation and explicit transient formulation are used.

time_step_size(*args, **kwargs)#: Sets the magnitude of the (physical) time step . This text command is only available when the solve/set/transient-controls/fixed-user-specified text command is set toyes.

time_step_size_for_acoustic_export(*args, **kwargs)#: Specifies the time interval for acoustic data sampling. This text command is only available when both the Ffowcs Williams and Hawkings model is selected and the density-based solver is used with the explicit formulation and explicit transient formulation.

total_number_of_time_steps(*args, **kwargs)#: Sets the total number of time steps that the simulation will run (which includes any time steps that have already been run in previous calculations). This text command is only available when the solve/set/transient-controls/duration-specification-method is set to1.

total_time(*args, **kwargs)#: Sets the total amount of time that the simulation will be run (which includes any time that has already been run in previous calculations). This text command is only available when the solve/set/transient-controls/duration-specification-method is set to2.

udf_based_time_stepping(*args, **kwargs)#: Allows you to specify that the time step size is defined by a user-defined function (UDF) that uses theDEFINE_DELTAT macro.

undo_timestep(*args, **kwargs)#: When enabled, if the truncation error within a time step exceeds the specified tolerance Fluent will automatically undo the current calculation and make another attempt with the time step reduced by 1/2. This will be attempted up to 5 times after which Fluent will accept the result and proceed to the next time step.