8.2.1. Expression Editor Dialog Box

The Expression Editor dialog box contains:

  • A tree view for viewing and managing expressions (The tree view has a shortcut menu with commands for creating/deleting/modifying expressions, as described below.)

  • A details view for creating/editing/displaying the definition of the new/selected expression

    (You can find a list of valid CEL expressions and constants in Ansys CFX Expression Language in the TurboGrid Reference Guide.)

  • A Value box to show the value of the selected expression when the expression does not contain variables and evaluates to a single value.

You can right-click an existing expression or a blank area in the tree view portion of the Expression Editor dialog box in order to access a shortcut menu with the following commands:

Table 8.1: Expression Editor Shortcut Menu Commands

Command

Description

Edit

Displays the definition of the selected Expression in the details view portion of the Expression Editor dialog box, and gives it the keyboard focus. An alternative way to do the same is to double-click an expression in the tree view.

Insert > Expression

Opens the New Expression dialog box where you can enter a name for a new expression. After you enter a name, you must provide and apply a definition in order to finish creating the new expression.

When selecting an expression name:

  • You cannot create an expression with the same name as an object.

  • You cannot create an expression with the same name as a variable.

Edit in Command Editor

Invokes the Command Editor dialog box populated with the selected expression.

Delete

Deletes the selected expression.

Duplicate

Creates a duplicate of the selected expression after obtaining the name of the new expression from the New Expression dialog box.

Use as Workbench Input Parameter [a]

Makes the selected expression a Workbench input parameter so that it is available in, and controllable by, Ansys Workbench.

The Workbench input parameter is initialized by the expression definition specified in Ansys TurboGrid. The definition must be a function of only constants; units are permitted.

It is not possible to edit the value of an expression in Ansys TurboGrid while the expression is a Workbench input parameter.

Use as Workbench Output Parameter[a] [b]

Makes the selected expression a Workbench output parameter, causing it to be output from Ansys TurboGrid for use in Ansys Workbench.

Deselect as Workbench Parameter[a][b]

Removes the Ansys Workbench parameter status from the selected expression.

[a] You can enable/disable the use of a Workbench input parameter directly for many settings in the object editor. For details, see Object Editor.

[b] For details on Workbench parameters, see Working with Parameters and Design Points in the Workbench User's Guide


When defining an expression:

  • You cannot use a user variable.

  • Constants require units inside square brackets.

  • You can right-click in the details view to access a shortcut menu for inserting variables, locators, expressions, and functions into your equation.

 

8.2.1.1. Expression Editor Example

To define an expression for distance from the X axis:

  1. Select Tools > Expressions from the main menu to open the Expression Editor dialog box.

  2. When the New Expression dialog box appears, enter the name radial and click OK.

  3. In the details view portion of the Expression Editor dialog box, enter the following expression definition:

    sqrt(Y^2+Z^2)

  4. Click Apply to create the expression.

Note that the Value box does not show a value for the expression because the expression does not evaluate to a single value.

The expression created in this example (radial) is used in the Variable Editor Example.