# CONVERGENCE_CHECK_PARAMETERS

Specifies the parameters for fine tuning convergence checking.

## Type

AcuSolve Command

## Syntax

CONVERGENCE_CHECK_PARAMETERS {parameters}

## Qualifier

This command has no qualifier.

## Parameters

- pressure_residual_check or pres_res (enumerated) [=standard]
- Modifies the convergence check of the residual ratio of the pressure equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- pressure_solution_increment_check or pres_sol (enumerated) [=looser_by_10]
- Modifies the convergence check of the solution increment ratio of the pressure equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- velocity_residual_check or vel_res (enumerated) [=standard]
- Modifies the convergence check of the residual ratio of the velocity equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- velocity_solution_increment_check or vel_sol (enumerated) [=looser_by_10]
- Modifies the convergence check of the solution increment ratio of the velocity equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- temperature_residual_check or temp_res (enumerated) [=standard]
- Modifies the convergence check of the residual ratio of the temperature equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- temperature_solution_increment_check or temp_sol (enumerated) [=looser_by_10]
- Modifies the convergence check of the solution increment ratio of the temperature equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- radiation_residual_check or rad_res (enumerated) [=none]
- Modifies the convergence check of the residual ratio of the radiation equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- radiation_solution_increment_check or rad_sol (enumerated) [=looser_by_10]
- Modifies the convergence check of the solution increment ratio of the radiation equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- species_residual_check or species_res (enumerated) [=standard]
- Modifies the convergence check of the residual ratio of the species equations.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- species_solution_increment_check or species_sol (enumerated) [=looser_by_10]
- Modifies the convergence check of the solution increment ratio of the species equations.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- field_residual_check or field_res (enumerated) [=standard]
- Modifies the convergence check of the residual ratio of the phase-field transport equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- field_solution_increment_check or field_sol (enumerated) [=looser_by_10]
- Modifies the convergence check of the solution increment ratio of the phase-field transport
equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- levelset_residual_check or ls_res (enumerated) [=looser_by_10]
- Modifies the convergence check of the residual ratio of the level set transport equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- levelset_solution_increment_check or ls_sol (enumerated) [=looser_by_100]
- Modifies the convergence check of the solution increment ratio of the level set transport
equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- redistancing_residual_check or rdist_res (enumerated) [=looser_by_100]
- Modifies the convergence check of the residual ratio of the level set sharpening equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- redistancing_solution_increment_check or rdist_sol (enumerated) [=looser_by_100]
- Modifies the convergence check of the solution increment ratio of the level set sharpening
equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- turbulence_residual_check or turb_res (enumerated) [=looser_by_10]
- Modifies the convergence check of the residual ratio of the turbulence equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- turbulence_solution_increment_check or turb_sol (enumerated) [=looser_by_100]
- Modifies the convergence check of the solution increment ratio of the turbulence equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- transition_residual_check or ttm_res (enumerated) [=looser_by_100]
- Modifies the convergence check of the residual ratio of the transition model equations.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- transition_solution_increment_check or ttm_sol (enumerated) [=looser_by_1000]
- Modifies the convergence check of the solution increment ratio of the transition model
equations.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- viscoelastic_stress_residual_check or vest_res (enumerated) [=standard]
- Modifies the convergence check of the residual ratio of the viscoelastic stress equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- viscoelastic_stress_solution_increment_check or vest sol (enumerated) [=looser by 10]
- Modifies the convergence check of the solution increment ratio of the viscoelastic stress
equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- mesh_displacement_residual_check or mesh_res (enumerated) [=none]
- Modifies the convergence check of the residual ratio of the mesh displacement equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

- mesh_displacement_solution_increment_check or mesh_sol (enumerated) [=looser_by_100]
- Modifies the convergence check of the solution increment ratio of the mesh displacement
equation.
- none
- Performs no convergence check.
- standard or full
- Performs convergence check as is.
- looser_by_10 or loose_10
- Loosens the convergence check by a factor of 10.
- looser_by_100 or loose_100
- Loosens the convergence check by a factor of 100.
- looser_by_1000 or loose_1000
- Loosens the convergence check by a factor of 1000.
- tighter_by_10 or tight_10
- Tightens the convergence check by a factor of 10.
- tighter_by_100 or tight_100
- Tightens the convergence check by a factor of 100.
- tighter_by_1000 or tight_1000
- Tightens the convergence check by a factor of 1000.

## Description

This command specifies a set of factors useful for fine control over convergence checking of various residual and solution increment ratios.

The time stepping, stagger iteration and nonlinear iteration loops check for the convergence of the solution; see TIME_SEQUENCE command for a description. The convergence check is performed on the residual and solution increment ratios of each equation in the problem. For the residual, the ratio of the residual norm over the norm of the forces of the systems is used. For the solution increment, the ratio of the solution increment norm over the solution norm is used. These ratios are computed separately for each solution field, such as pressure, velocity and temperature.

```
TIME_SEQUENCE {
convergence_tolerance = 1.e-3
}
CONVERGENCE_CHECK_PARAMETERS {
pressure_residual_check = standard
pressure_solution_increment_check = none
velocity_residual_check = standard
velocity_solution_increment_check = looser_by_10
}
```

Steady state is declared when the pressure and velocity residual ratios are below 10-3 and the velocity solution increment ratio is below 10-2 . The pressure solution increment ratio is ignored.

The default parameters of the CONVERGENCE_CHECK_PARAMETERS command are chosen based on experience. You rarely need to change them.