Configuring Units in Workbench

Workbench provides:

  • Predefined unit systems that contain the most commonly used sets of units.

  • The ability to define custom unit systems based on the predefined unit systems. (You cannot edit or delete predefined unit systems.)

  • The ability to display the following project data using the project unit system:

    • Engineering data

    • Parameters

    • Charts.

  • The ability to share the unit system between users.

Note:  Unit settings in Workbench are not passed to Fluid Flow analysis systems; to CFX, Fluent, Results, or TurboGrid systems; or to FSI: Fluid Flow custom systems.

To open the Unit Systems dialog box, from the menu bar select Units > Unit Systems.

The Unit Systems dialog is displayed and contains the following options:

OptionDescription
  Active Project Sets unit system for active project.
  Default Sets default unit system. This will be default unit system for every project.
  Suppress/Unsuppress Hides/displays unit system menu item. Only 15 unit systems can be unsuppressed and displayed as in the Units menu.
DuplicateCreates a custom unit system based on selected unit system.
DeleteDeletes unit system. The following unit systems cannot be deleted:

  • Predefined Unit System

  • Active Project Unit System

  • Default Unit System

ImportImports a units file (*.xml).
ExportExports the active project unit system as a units file (*.xml).

Units

A unit system is a collection of the preferred unit for the base, common, and other quantity types.

  • Base Units: All other units are derived from these units.

    • Angle

    • Chemical Amount

    • Current

    • Length

    • Luminance

    • Mass

    • Solid Angle

    • Time

    • Temperature

  • Common Units: These are units which are derived from the base units and are typically used as base units for other units.

    • Electric Charge

    • Energy

    • Force

    • Power

    • Pressure

    • Voltage

  • Other Units: Several other units are derived from base and common units.

For a detailed description on how units are used in expressions, see Expressions, Functions, Quantities, and Units.

Predefined Unit Systems

Workbench offers the following predefined unit systems:

  • Metric (kg, m, s, °C, A, N, V) (default unit system)

  • Metric (tonne, mm, s, °C, mA, N, mV)

  • U.S. Customary (lbm, in, s, °F, A, lbf, V)

  • SI (kg, m, s, K, A, N, V)

  • U.S. Engineering (lbm, in, s, R, A, lbf, V)

You cannot edit or delete predefined unit systems.

Workbench also provides the following additional unit systems. These are suppressed by default.

  • Metric (g, cm, s, °C, A, dyne, V)

  • Metric (kg, mm, s, °C, mA, N, mV)

  • Metric (kg, µm, s, °C, mA, µN, V)

  • Metric (decatonne, mm, s, °C, mA, N, mV)

  • U.S. Customary (lbm, ft, s, F, A, lbf, V)

  • Consistent CGS

  • Consistent NMM

  • Consistent µMKS

  • Consistent BIN

  • Consistent BFT

For a detailed description of unit systems for the Mechanical application, see Understanding Solving Units in the Mechanical User's Guide.

You can also display values as defined and display values in project units. See Units Menu for more information on using these options.

Custom Unit Systems

To create a custom unit system based on a predefined unit system, select the unit system and click Duplicate.

  • The default name for the new Unit system is Custom Unit System. You can change the name.

  • You can change the units for any quantity type from the available list.

  • The list of units that are available are either consistent with SI or US Customary, depending on the original unit system. This to assure that a consistent unit system can be constructed for solution purposes.

  • Changing base units can automatically change Common and Other derived units if appropriate. For example, if the mass unit is kg, the length unit is m, and the force unit is N, then changing mass to g and length to cm will automatically change force to dyne.

Unit Limitations

Sound Pressure Level and A Weighted Sound Pressure Level are dimensionless quantities with units dB and dBA, respectively.

  • Math operations between these two units or either of these and a numerical value will result in a value with no unit. For example, 10 dB x 10 = 100. (no unit)

  • Math operations between either of these units and a dimensional unit will result in a value with the dimensional unit. For example, 10 dB x 10 m = 100 m.