2.2 Using the Update Command

The Update command is available from the context menu of all cells, from the context menu for the system, and from the Workbench Toolbar, the Workbench Tools menu, and the context menu for the Project Schematic.

When selected from a cell, the Update command updates the current cell and all upstream cells that must be updated to bring the current cell Up-to-Date. When a cell is updated, any new upstream data is passed to it before performing the update command.

When selected from the system, the Update command updates all of the out-of-date cells in the current system, as well as any cells in upstream systems that must be updated to bring the current system Up-to-Date.

When selected from the Workbench Toolbar, the Workbench Tools menu, or the context menu for the Project Schematic, the Update command updates all out-of-date cells in the project.

When updating the Solution cell in a FLUENT system, the following steps take place:

1.    FLUENT launches in the background.

2.    FLUENT performs either the number of iterations (or time-steps) specified in the settings or case file or the number of iterations required to reach convergence.

3.    FLUENT writes the case and data files.

4.    FLUENT exits.

When an update is performed on a Solution cell and a FLUENT session from the same system as that Solution cell is open, the calculation will be performed in that open FLUENT session. This may not result in the action that you intended, therefore it is recommended that you close any open FLUENT sessions before executing an Update command. For example, if you have specified initial data using either a connection from an upstream solution cell or by importing initial data into the Solution cell and you open FLUENT from the Setup cell of the system, the initial data is not loaded (see Section  1.5.1). If you subsequently perform an Update, the calculation will be performed in the open FLUENT session and the initial data you specified will not be used as the starting point.

The Update command is particularly useful when you make changes to upstream data that impact downstream data. For example, if you start with an Up-to-Date Fluid Flow (FLUENT) analysis system and then modify the mesh in the ANSYS Meshing application, you can simply select Update from the system's context menu to generate the new results.

When performing an Update, you can specify whether the Solution cell in a FLUENT-based system should be updated starting from the current data file or from the initial data. This is specified by selecting or deselecting the Update from Current Solution Data if Possible option from the context menu of the Solution cell. This option is enabled when there is a check mark to its left. This option is always enabled when you create a new system.

Initial data can be specified in four ways:

• On the Solution Initialization task page in FLUENT.

• Import an initial data file into the Solution cell or the FLUENT application (see Section  2.1).

• Create a connection from an upstream Solution cell (see Section  2.6).

• Specify a case modification strategy (see Section  2.9).

If you have imported an initial data file or created a connection to specify initial data, that data will override the initialization method specified on the Solution Initialization task page. If you have a case modification strategy defined, the initialization step in that strategy will always be performed regardless of whether initial data is specified in any other way.

If the Solution cell in a FLUENT-based system is connected to the Solution cell in an upstream system, the Import Initial Data... option is not available from the context menu of the downstream Solution cell. If you want to import initial data into the downstream Solution cell, you must delete the connection first. Similarly, if the Solution cell already has imported initial data, a connection cannot be made to that cell from the Solution cell in an upstream system. Furthermore, you cannot create a connection from the Solution cell in an upstream system to any Solution cell in which you have ever imported initial data.

When you select Update from the Setup cell in a FLUENT-based system and a FLUENT session is not already open, a FLUENT session launches in background mode. After the Update is complete, the background session of FLUENT remains open and waits for you to update the Solution cell. To close the open background session of FLUENT without updating the Solution cell, you can select the Close FLUENT Session option from the Setup cell's context menu.

There is also an Update command in the ANSYS Meshing application which generates the mesh and creates the input files required by downstream cells. The Generate Mesh command in the ANSYS Meshing application generates the mesh but does not produce any input files. If a connection is made from an up-to-date Mesh cell, the state of the Mesh cell may become Update Required, indicating that the ANSYS Meshing application needs to generate an additional input file. This file can be generated by selecting the Update option from the context menu of the Mesh cell. If you try to open FLUENT before the Mesh cell is updated, a warning message is displayed informing you that you must update the Mesh cell before you can start FLUENT, since the mesh file required for FLUENT does not yet exist.

Whether you edit the project through the Setup or Solution cells, your project's post-processing settings in FLUENT (including any surface definitions that you may have created), are saved at the start of iteration or when you close FLUENT. When FLUENT is later opened from either cell, these new settings will be available. Changes made to post-processing settings in FLUENT do not affect cell state.