Setting wave celerity

Wave celerity is used by:

• The transients advisor to calculate results that can be used as an indicator of potential problem areas due to transient pressures
• InfoWorks TS to calculate transient system simulation results

The wave celerity of pipes in the network can be automatically set based on the pipe material. However, this functionality allows only one wave celerity value per pipe material to be set from the Pipe Materials dialog. For more information on wave celerity values see the Transients Advisor topic.

The wave celerity lookup uses the list of materials defined on the Pipe Materials dialog.

Looking up values in the pipe materials table depends on having an appropriate entry in the Material field of the pipe. No changes will be made if:

• the pipe Material field does not contain an entry
• the value in the pipe Material field does not match one of the available types in the Pipe Materials dialog

Default wave celerity values are provided for a default set of materials in the Pipe Materials dialog. These defaults can be changed and additional pipe materials can be created. See the Pipe Material and Automated Lookup topic for more details.

Lookup methods

There are two methods of carrying out the lookup

• Select a number of cells in the Wave Celerity column of the pipe grid view, right click and select Current cell(s) value Lookup new value(s) for cell(s), or
• select Set celerity of pipes from the Model menu. There are various methods you can use to limit the pipes affected by the changes (see below).

Because these methods replace current values in the grid with new lookup values, it is probably a good idea to back up the existing values, and mark values that have changed with a special flag.

Model menu

To make changes to the wave celerity values of some, or all, pipes you can use the option on the Model menu. InfoWorks WS Pro will change all wave celerity values for pipes that meet the criteria listed above.

However, you can be more selective about what pipes are changed in several ways. You can:

• limit the pipes covered by the lookup by using a selection
• prevent changes to any pipe that already has a wave celerity value set
• prevent changes to pipes with a specified flag on the wave celerity field.

If you intend to change existing wave celerity values, we recommend that you store a copy of the original wave celerity values before carrying out this procedure. See Backing up old values below.

1. Choose Set celerity of pipes from the Model menu. This displays the Set Value From Lookup Table dialog. Note that the Model menu is visible only when there is a network open, and one of the network views is the current active window.
2. If required, limit the objects affected by the changes:
   • Check Selected Objects Only to limit the changes to the currently selected pipes.
   • Choose the Leave Existing Wave Celerity Values Unchanged option to protect existing values in this field.
   • Choose the Overwrite Unless Have Flag option, and select a flag in the dropdown list. This prevents changes to any pipe where the wave celerity field has the chosen flag.
3. Create a special flag to mark wave celerity values changed using this procedure:
   • Select the flag in the Set wave celerity values flag to box.

   This flag will be applied to all wave celerity fields that have been changed.

Context menu

To make changes to a series of wave celerity values using the context menu

1. Select one or more wave celerity value cells.
2. Right-click any of the selected cells, and choose Current cell(s) value Lookup new value(s) for cell(s).

   This displays the Set Value From Lookup Table dialog.

   If you select cells that are disabled, or where the Material is not set, the menu option will be unavailable.

The options from the dialog are the same as for the Model menu method (in steps 2 and 3, above).

Backing up old values

Note: It is very important to remember that the existing wave celerity value is REPLACED when you carry out this procedure, unless you choose the Leave existing wave celerity values unchanged option. This replacement cannot be undone.

We recommend that you back up the wave celerity values in some way if you do intend to change existing values, so you can return to them if the automatically updated values are not appropriate.

One method would be to check the network in and then check out again so the old values are stored in the database in a previous version of the network.

A more flexible method is probably to copy the data from the wave celerity column of the grid and paste it into one of the User Number columns (or User Text if you do not have a numeric column available).

To copy the data

1. Select all the cells in the column and choose Copy from the Edit menu, or press Ctrl-C. If you select the entire column by clicking the column header, make sure you click No when asked if you want to include the column header.
2. Click the top cell of the User column where you want to paste the data. Make sure you scroll the grid back to the top if necessary.
3. Choose Paste from the Edit menu, or right click and choose Paste from the context menu, or press Ctrl-V to paste the data into the new column.
4. If you want to show what data it now contains, rename the column. See Renaming Additional User Fields.

If you combine this procedure with a special flag set to mark changed values (see above), it is easy to see what InfoWorks WS Prohas changed, and to go back to the old value if the change is inappropriate.

Moving the User Number column next to the Wave Celerity column will make comparison even easier.