5.1 Restrictions on Units

It is important to note that the units for some inputs in ANSYS FLUENT are different from the units used for the rest of the problem setup.

• You must always define the following in SI units, regardless of the unit system you are using:
  • boundary profiles (see Section  7.6)

  • source terms (see Section  7.2.5)

  • custom field functions (see Section  31.5)

  • data in externally-created XY plot files (see Section  29.9.3)

  • user-defined functions (See the separate UDF Manual. for details about user-defined functions.)

• If you define a material property by specifying a temperature-dependent polynomial or piecewise-polynomial function, remember that temperature in the function is always in units of Kelvin or Rankine. If you are using Celsius or Kelvin as your temperature unit, then polynomial coefficient values must be entered in terms of Kelvin; if you are using Fahrenheit or Rankine as the temperature unit, values must be entered in terms of Rankine. See Section  8.2 for information about temperature-dependent material properties.