A rapid change in the demand at junction can produce a transient. This can be used to simulate a hydrant opening or any rapid change in demand that may have the potential to produce transient pressure change in the system.

  1. Click on the Select  button of the Attribute Browser window, and then click on the Select Junction  menu. Select the model junction for the demand change.

  2. Click on the Demand Change button on the Surge toolbar. The Junction Demand Change Data dialog box appears on the screen.

  3. Choose either an existing Demand Change Curve from the drop-down list or click on the Browse  button to the right to create a new curve or edit an existing one.

  4. Click on the Create button to close the Demand Change dialog box.

Example - An external demand of 45 gpm is held for 2 seconds and then ramps up to 1,200 gpm over the next 4 seconds.