Performing the Hydraulic Calculations

Now that all of the data have been entered, we can calculate the steady water surface profiles. To perform the simulations, go to the HEC-RAS main window and select Steady Flow Analysis from the Run menu. The Steady Flow Analysis window should appear as shown in Figure 4.10, except yours will not have any plan titles yet.

Figure 4.10 Steady Flow Analysis Simulation Window

The first step is to put together a Plan. The Plan defines which geometry and flow data are to be used, as well as providing a title and short identifier for the run. To establish a plan, select New Plan from the File menu on the Steady Flow Analysis window. Enter the plan title as "Existing Conditions Run" and then press the OK button. You will then be prompted to enter a short identifier. Enter a title of "Existing" in the Short ID box.

The next step is to select the desired flow regime for which the model will perform calculations. For this example we will be performing Subcritical flow calculations only. Make sure that Subcritical is the selected flow regime. Additional job control features are available from the Options menu bar, but none are required for this example. Once you have defined a plan and set all the desired job control information, the plan information should be saved. Saving the plan information is accomplished by selecting Save Plan from the File menu of the Steady Flow Analysis window.

Now that everything has been set, the steady flow computations can be performed by pressing the Compute button at the bottom of the Steady Flow Simulation window. Once the compute button has been pressed, a separate window will appear showing you the progress of the computations. Once the computations have been completed, the computation window can be closed by double clicking the upper left corner of the window. At this time the Steady Flow Simulation window can also be closed.

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