6.5. Time Control

This section is referenced in the following other sections

Simulation Setup: Time Control

6.5.1. Time Control

Scope: Fuego Procedure
Summary: Defines the time control for the problem in the procedure scope.
Description: This describes the Time Control block which is convenient for single-physics applications. The Solution Control block is described elsewhere, and is appropriate for multiphysics applications.

begin Time Control

   Termination Time {=} Tend

   begin Time Stepping Block BlockName
   end

end Time Control

6.5.1.1. Line Commands

Termination Time

Syntax: Termination Time {=} Tend
Summary: Specifies the ending time for this solution period.

Parameter	Value	Default
{=}	{= \| are \| is}	–
Tend	real	–

6.5.2. Time Stepping Block

Scope: Time Control
Summary: Defines the time and time step parameters for a solution period.

begin Time Stepping Block BlockName

   Number Of Time Steps {=} Nsteps

   Start Time {=} Tstart

   Time Step {=} Dt0

   begin Parameters For Fuego Region RegionName
   end

end Time Stepping Block BlockName

6.5.2.1. Line Commands

Number Of Time Steps

Syntax: Number Of Time Steps {=} Nsteps
Summary: Specifies the number of time steps in this solution period.

Parameter	Value	Default
{=}	{= \| are \| is}	–
Nsteps	integer	–

Start Time

Syntax: Start Time {=} Tstart
Summary: Specifies the starting time for this solution period.

Parameter	Value	Default
{=}	{= \| are \| is}	–
Tstart	real	–

Time Step

Syntax: Time Step {=} Dt0
Summary: Specifies the time step size for this solution period.

Parameter	Value	Default
{=}	{= \| are \| is}	–
Dt0	real	–

6.5.3. Parameters For Fuego Region

Scope: Parameters For
Summary: Defines region-specific time stepping data.

begin Parameters For Fuego Region RegionName

   Cfl Limit {=} Clfmax

   Iteration At Skip Step {=} SkipIter

   Maximum Time Step {=} DtMax

   Minimum Time Step {=} DtMin

   Skip Step {=} SkipStep

   Skip Steps For Pmr {=} PMRSkip

   Time Step Change Factor {=} Change

   Transient Step Type {=} {automatic | fixed | invalid time step type}

end Parameters For Fuego Region RegionName

6.5.3.1. Line Commands

Cfl Limit

Syntax: Cfl Limit {=} Clfmax
Summary: Specifies the maximum value of the CFL number that is used to determine the auto time step.
Description: Need a fuller description here.

Parameter	Value	Default
{=}	{= \| are \| is}	–
Clfmax	real	0.5

Iteration At Skip Step

Syntax

Iteration At Skip Step {=} SkipIter

Summary

Controls the number of iterations in between a skip step.

Description

This is the first implementation of the ability to freeze the Fuego region and allow time advancement without a Fluids/Conduction solve. In the near future, solution control will allow this feature in a more elegant manner.

For now, the iteration count will allow for a given number of iterations when the Afgo regions solve is “active”, that is not during a skip step.

Parameter	Value	Default
{=}	{= \| are \| is}	–
SkipIter	integer	–

Maximum Time Step

Syntax: Maximum Time Step {=} DtMax
Summary: Specifies the maximum allowable time increment for auto timestepping.
Description: Need a fuller description here.

Parameter	Value	Default
{=}	{= \| are \| is}	–
DtMax	real	1.0e12

Minimum Time Step

Syntax: Minimum Time Step {=} DtMin
Summary: Specifies the minimum allowable time increment for auto timestepping.
Description: Need a fuller description here.

Parameter	Value	Default
{=}	{= \| are \| is}	–
DtMin	real	0.0

Skip Step

Syntax: Skip Step {=} SkipStep
Summary: Controls the frequency of Fuego (Afgo) iteration.
Description: This is the first implementation of the ability to freeze the Fuego region and allow time advancement without a Fluids/Conduction solve. In the near future, solution control will allow this feature in a more elegant manner.

Parameter	Value	Default
{=}	{= \| are \| is}	–
SkipStep	integer	–

Skip Steps For Pmr

Syntax: Skip Steps For Pmr {=} PMRSkip
Summary: Controls the frequency of PMR solve.
Description: Set the PMR solve interval. Default is 1 (every step).

Parameter	Value	Default
{=}	{= \| are \| is}	–
PMRSkip	integer	1

Time Step Change Factor

Syntax: Time Step Change Factor {=} Change
Summary: Specify the factor by which the time step is allowed to increase or decrease between time steps.
Description: Need a fuller description here.

Parameter	Value	Default
{=}	{= \| are \| is}	–
Change	real	10.0

Transient Step Type

Syntax: Transient Step Type {=} {automatic | fixed | invalid time step type}
Summary: Specifies whether to use fixed time-stepping or automatic time-stepping.
Description: Need a fuller description here.

Parameter	Value	Default
{=}	{= \| are \| is}	–
FuegoStepType	{automatic \| fixed \| invalid time step type}	FIXED