Initial Conditions

Unlike boundary conditions, initial conditions are only enforced at the beginning of the analysis. They are primarily used for transient analyses, but sometimes (temperature, in particular) they are useful for steady state analyses.

Initial Condition Task Visibility

If you do not see the Initial Condition command in the Setup (tab) or the Design Study Bar, do the following to enable it:

1. Click the Application Menu button (in the top left corner).
2. Click Options.
3. In the Display tab, change the setting for Show initial conditions task icon to Yes.

Initial Conditions Types

There are seven quantities that can be assigned as initial conditions:

• Velocity
• Pressure
• Temperature
• Scalar
• Humidity
• Quality
• Height of Fluid

For more information about each of these quantities, click here.

All can be applied to surfaces or volumes, except Height of Fluid, which is only a volumetric condition.

Use the Height of Fluid condition to specify the initial location of liquid in a free surface simulation.

To apply an initial condition

1. Choose the Selection Mode (volume, surface, or edge) from Setup (tab) > Selection (panel).
2. Click Edit on the Initial Conditions context panel.
3. Select the entity.
4. Set the Type of condition.
5. Set the Units (if applicable).
6. Check to Re-initialize the condition. For a transient simulation that has been run, use Re-initialize to reset the condition on the selected part or parts to the prescribed value. An example is to re-initialize the temperature after the flow solution has completed to see how the temperature varies with time.
7. Specify the value.
8. Apply condition-specific settings such as Static or Total for Temperature or Static or Gage for Pressure. (Different initial condition types require different numbers of entries.)
9. Click Apply.

The Remove button deletes the selected initial condition type from the selected entities.