When all geometric data and flow data are entered in the model, the user can perform the hydraulic calculations. In GeoHECRAS, the Compute Steady – Current Scenario command allows the user to perform an analysis of the current scenario (plan) for steady flow models.
This command also allows the user to select specific profiles to analyze, rather than analyzing all of the defined profiles. For example, the steady flow model contains the 2-Year, 5-Year, 10-Year, 25-Year, 50-Year, and 100-Year profiles. The user can select any profile(s) to analyze from the list of available profiles.
Follow the steps below to use the Compute Steady – Current Scenario command for steady flow analysis:
- From the Analysis ribbon menu, click the Compute Steady dropdown combo box and select the Current Scenario command.
- The Compute Steady – Current Scenario dialog box will be displayed.
The following sections describe how to use the Compute Steady – Current Scenario command and interact with the above dialog box.
This section allows the user to define the scenario data to be used in the steady flow simulation.
The following parameters are provided in the Scenario Data section:
- Scenario (plan)
This dropdown combo box allows the user to select the scenario for which the analysis will be performed. The dropdown combo box lists all the steady flow scenarios that are already defined in the project. By default, the current scenario is selected.
This read-only field contains the corresponding geometry for the selected scenario.
- Steady flow
This read-only field contains the corresponding steady flow for the selected scenario.
This section allows the user to define the flow regime to be computed by the HEC-RAS steady flow analysis engine. In addition, the computational log file can be created from this section.
The following options are provided in the Computational Options section:
- Flow regime
This dropdown combo box is used to select a flow regime for which the model will perform calculations. The following options are available in the dropdown combo box:
- Subcritical flow: This option requires only downstream boundary conditions. By default, this option is selected.
- Supercritical flow: This option requires only the upstream boundary conditions.
- Mixed flow: This option requires both upstream and downstream boundary conditions.
- Create computational log file, detail level
This checkbox option is used to create a computational log file computed by the HEC-RAS steady flow analysis engine. The spin control defines the level of the log file for a steady flow analysis. By default, the software uses a value of 3. However, the user can enter a different value ranging from 0 to 10, with 0 resulting in no log output and 10 resulting in the maximum log output.
Note that the computational results log file can be seen from the View Log File command of the Results ribbon menu.
Profile Analysis Selection
This section allows the user to select the profile to be analyzed.
This section has a table that lists all profiles defined in the project. The user can select the desired profile by checking the checkboxes available in the Perform Analysis column corresponding to each profile name available in the Profile Name column to display the output result. By default, all profiles are selected.
The user can click the [Select All] button to analyze all selected profiles listed in the table.
The user can click the [Clear All] button to cancel all the profiles selected in the table and redo the entire process.
Computing Steady Flow Analysis
When all the options have been properly defined, click the [Compute] button. This will cause HEC‑RAS to perform the analysis for the current scenario. Note that the Compute Steady – Current Scenario dialog box will be closed on clicking the [Compute] button.
If a problem is detected in the model data or analysis, the software will display a dialog box detailing the issue and will stop the process. Otherwise, the HEC-RAS Finished Computations dialog box will be displayed once the computations are finished. Click the [Close] button to close the dialog box.