Merging two different projects (Geometry)

1. Open up HEC-RAS.

 

2. From File menu click on Open Project. (For example open Project 1)



3. Then from Edit menu click on Geometric Data.



4. From Geometric Data window click on File menu > Import Geometry Data > HEC-RAS Format.



4. The below mention dialog box will appear. From the dialog box navigate to the project location and select the geometry file*g* of Project 2 and click on OK.



5. From the Import Geometry Data dialog box define the geometry that you want to import and click on Finised - Import Data.

 

6. After clicking on Finished - Import Data the geometries will be merged into one single project. Go over to File menu and click on Save Geometry Data.

Switching Between Different Plans

1. Open up your project in HEC-RAS.

 2. From Run menu click on Steady Flow Analysis or Unsteady Flow Analysis.

3. From the Flow Analysis Window click on File menu and select Open Plan.

 

4. From the Open Plan dialog box select the plan that you want to open.

Setting Default Project Folder

1. Open up HEC-RAS.

2. From Options menu click on Program Setup > Default Project Folder.



3. From the Select Folder dialog box define the directory and the folder. Click on OK.

Changing Project Units

1. Open up HEC-RAS.

 2. From Options menu click on Unit System.

3. Below mentioned dialog box will appear. In the dialog box select the units system and click on OK button.

4. To set the selected unit system as a default check the box "Set as default for new projects".

Normal Flow vs Gradually-Varied Flow

In normal flow the down-slope component of weight balances bed friction. As a result, the
water depth h and velocity V are constant and the total-head line (or energy grade line) is
parallel to both the water surface and the channel bed; i.e. the friction slope Sf is the same as
the geometric slope S0.

As a result of disturbances due to hydraulic structures (weir, sluice, etc.) or changes to
channel width, slope or roughness the downslope component of weight may not locally
balance bed friction. As a result, the friction slope Sf and bed slope S0 will be different and
the water depth h and velocity V will change along the channel.
The gradually-varied-flow equation gives an expression for dh/dx and allows one to predict
the variation of water depth along the channel.

Types of Open channel flow

Steady Flow:

For open channel, the flow is steady if the depth of flow does not change with respect to time at a particular location or section.

Uniform flow:

For open channel flow, the flow is uniform if the depth of flow remains constant along a certain length of the channel.

Non Uniform flow:

For open channel flow, the flow is non uniform if the depth of flow does not remains constant along a certain length of the channel.

Gradually Varied flow:

If the depth of flow changes over a relatively long distance along the length of a channel, then the flow is called gradually varied flow.

Rapidly Varied flow:

If the depth of flow changes over a relatively short distance along the length of a channel, then the flow is called rapidly varied flow.

Modeling procedure for separate channel splits

 1. For a split flow optimization, first of all we need to estimate the initial supplies of the total flow in both separate channels. HEC-RAS will then uses these initial flow estimates to perform computation from downstream to upstream on both the channels.

2. From Steady Flow Analysis click on Options and select Flow Optimization and under the Flow Optimizations dialog box you need to select the check box for Junction.

3. When the junction tab is selected, perform the analysis by computing the water surface profiles for all the reaches.

4. Then compare the computed energy grade lines for the cross section just downstream of the junction.

5. If the energy in all the reached below the junction is not within a specified tolerance (0.02 feet). Then the flow going to each reach is re-distributed and the profiles are re-calculated.

6. The methodology continues until a balance is reached.