### 21.1.8. Common Settings

#### 21.1.8.1. Option

- `Selected Variables`

  Selected vertex fields are written to the results file. The fields are chosen from the Output Variables List. No clean restart is possible from these files.

- `Boundary Only` (available only on the Trn Results tab)

  The selected transient results are written only to the vertices on the boundaries, reducing the size of each .trn file but also restricting the variable data available for postprocessing to that on the boundaries. Interior data will be undefined and, as such, this option is not recommended for postprocessing moving mesh simulations. Where available, hybrid data from each requested variable will be written, otherwise conservative values will be used. Data is not exported on symmetry boundaries or 1:1 periodic interfaces.

- `Smallest` (not available on the Results tab)

  Mesh data and all solution vertex fields are written. A restart is possible from these files, but the restart will not be clean (you can expect a temporary increase in residual values).

- `Essential`

  The smallest file that preserves a clean restart is written. This includes data written in the Smallest category and the following:

  - GGI control surface fields

  - Boundary face solution arrays

  - Mass flow data fields

- `Standard`

  This contains data written in the Essential category and the following:

  - Hybrid fields

  - Postprocessing fields

- `None`

  Used when no output of results is required (for example, during solver performance benchmarking).

#### 21.1.8.2. File Compression

- `None`

  This offers no compression.

- `Default`

  This is a compromise between disk space and processing load.

- `Best Speed Least Compression`

- `Low Speed Most Compression`

You may want to increase the compression level for large backup files, or if you do not have much disk space.

#### 21.1.8.3. Output Variables List

Allows you to select the output variables to write to the results file. Select the desired variables from the list or click the icon to select from a list of all variables. Output Variable List is available only when the option is set to `Selected Variables` or `Boundary Only`.

#### 21.1.8.4. Output Equation Residuals Check Box

When Output Equation Residuals is set to `All`, the equation residuals for all equations are written to the results file for steady-state solutions. The residuals can then be viewed in CFD-Post. They appear as ordinary variables available from the full list of variables. This parameter replaces the expert parameter `output eq residuals`.

#### 21.1.8.5. Output Boundary Flows Check Box

When Output Boundary Flows is set to `All`, equation flows, including mass flows, are written to the file you have set up. These flows enable accurate evaluations of forces, heat flows, and mass flow related calculations in CFD-Post. These flows are always written for `Standard` backup/results and transient files. They are not written for `Selected Variables` and `Smallest` transient files, unless the Output Boundary Flows parameter is set to `All`.

#### 21.1.8.6. Output Variable Operators Check Box

When Output Variable Operators is set to `All`, you get all available operators that the solver has calculated (for example, gradients, High Resolution betas) for the variables in the Output Variables List. This option only applies to minimal transient results files, selected variables, backup results and results files. These operators are always written for `Standard` files, but may also be written for `Selected Variables` and `Smallest` files by setting this parameter to `All`.

#### 21.1.8.7. Output Particle Boundary Vertex Fields Check Box

For cases with particles, when Output Particle Boundary Vertex Fields is selected, the following boundary vertex fields are written:

- Inlets, outlets, openings and interfaces:

  - Mass flow density

  - Momentum flow density

  - Energy flow density

- Walls:

  - Mass flow density

  - Stress

  - Erosion rate density.

For transient cases, the following additional boundary vertex fields are written:

- Inlets, outlets, openings and interfaces:

  - Time integrated mass flow density

  - Time integrated momentum flow density

  - Time integrated energy flow density

- Walls:

  - Time integrated mass flow density

  - Time integrated erosion rate density.

For additional details, see Particle Boundary Vertex Variables in the CFX Reference Guide

#### 21.1.8.8. Output Frequency Options

This determines how often backup and transient results files are written during a run.

##### 21.1.8.8.1. Timestep Interval

Enter a number that specifies the number of timesteps between the writing of each results file.

##### 21.1.8.8.2. Timestep List

Enter a comma-separated list of timestep numbers that specifies the timesteps at which files are written.

##### 21.1.8.8.3. Time Interval

Enter a number that specifies the simulation time interval between the writing of each file. The simulation time interval is added to a running total that starts at the simulation start time. An iteration within half a timestep of the current total has a file written.

##### 21.1.8.8.4. Time List

Enter a comma-separated list of simulation times that specifies the iterations at which files are written.

##### 21.1.8.8.5. Every Timestep

No further input is needed. A backup or transient results file is written for every timestep in a transient simulation.

##### 21.1.8.8.6. Every Iteration

No further input is needed. A backup or transient results file is written for every iteration.

##### 21.1.8.8.7. Iteration Interval

Enter a number that specifies the number of iterations between the writing of each file.

##### 21.1.8.8.8. Iteration List

Enter a comma-separated list of iteration numbers that specifies the iterations at which files are written.

##### 21.1.8.8.9. Wall Clock Time Interval

(Only available for backup files)

Enter a number that specifies the wall clock time interval between the writing of each backup file.

This is used to create backup files every so often in real time. For example, on an overnight simulation you might choose to have a backup file created every two hours, regardless of how many iterations or timesteps had been performed.

##### 21.1.8.8.10. Coupling Step Interval

(Only available for ANSYS Multi-field runs). Enter a number that specifies the number of coupling steps (multi-field timesteps) between the writing of each file. Note that if you are using CFX-Pre in `ANSYS MultiField` mode to set up the multi-field part of an ANSYS Multi-field run, then selecting this option has implications for how often the ANSYS Solver writes its results, in addition to specifying how often CFX should write results. For details, see The Processing Step in the CFX-Solver Manager User's Guide.

##### 21.1.8.8.11. Every Coupling Step

(Only available for ANSYS Multi-field runs). This is used to create a results file every coupling step (multi-field timestep). Note that if you are using CFX-Pre in `ANSYS MultiField` mode to set up the multi-field part of an ANSYS Multi-field run, then selecting this option has implications for how often the ANSYS Solver writes its results, in addition to specifying how often CFX should write results. For details, see The Processing Step in the CFX-Solver Manager User's Guide.

##### 21.1.8.8.12. None

No results files will be written. You might choose this option to temporarily turn off writing backup or transient files but keeping the definition of what to include in the files so that you can easily re-enable them.

Release 18.2 - © ANSYS, Inc. All rights reserved.