This tutorial document will guide you how to setup a coastal hydrodynamic model by using the EFDC_Explorer (EE). It will cover preparation of the necessary input files for the EFDC model and visualization of the output by using the EFDC_Explorer (EE) Software.
The data used for this tutorial are from Tra Khuc Estuary in Vietnam. All files for this tutorial are found in Data folder downloadable from the EEMS website.
Before going to each session, let us first introduce the EE main form in order to better understand our explanation hereafter. Figure 1 is the main form of EFDC_Explorer or EE User Interface. The functions of individual icons are described in Knowledge Base.
Figure 1 EFDC Explorer main form.
This section will guide you in how to create a new simple gird with EFDC_Explorer. For a complicated grid the user is recommended to use specialized grid generation software such as CVLGrid or Delft3D-RGFGRID.
Tra Khuc Estuary in Quang Ngai province, Vietnam is chosen as the example of building a 3D coastal model in EE.
The gird generation process includes following steps:
Figure 2 Generate EFDC Model form.
Figure 3 New created grid information.
5. Save the model by selecting this button and create a new directory as shown in Figure 4.
Figure 4 New model saved.
This section will guide you in how to assign the initial conditions such as the bathymetry, water level and bottom roughness.
Figure 5 Assigning the initial conditions.
Figure 6 Assigning the bathymetry.
The next step is to assign the initial depth or water surface elevations. There are two options for setting the surface water elevation which are Use Constant and Use Point Measurements/Gridded Data.
Figure 7 Assigning water surface elevation.
Figure 8 Assigning bottom roughness.
This section will guide you how to prepare for the boundary conditions and assign it to the model cell configuration. In this coastal case there are two flow boundaries; one is river discharge from the upstream and the other is tidal level. Thus, we should prepare two time series of inflow and tidal level boundaries for this particular case. In order to set a boundary time series the steps outlined below should be taken.
Click to the Current button to view the current time series. If there are a number of layers then check Sum Layers to show total flow. (See Figure 11). Close timeseries data plot
Click OK button in Data Series: Flow form to finish editing the boundary time series.
Figure 9 Assigning flow boundary conditions.
Figure 10 Editing the boundary time series (01).
Figure 11 Editing the boundary time series (02).
Figure 12 Flow time series plot.
Another option for setting the open boundary is the Harmonic Boundary Series (Harmonic Boundary Series)
Figure 12 Assigning tidal boundary conditions.
Figure 13 Preparing the tidal boundary series.
Figure 14 Tides time series plot.
When all required boundary time series are prepared the next step is to assign those boundary time series to the model cells. Figure 14 shows the location of inflow and tidal level for the TraKhuc case.
In order to assign the flow boundary, the following steps should be taken
Figure 15 Locations of inflow and open tidal boundaries.
Figure 16 Assigning boundary condition cells.
Figure 17 Create new boundary condition with RMC on the inflow cell.
Figure 18 Assign the corresponding time series.
Figure 19 Assigning boundary cells by a polyline.
Figure 20 Assigning BC to all selected cells.
Figure 21 Upstream BC cells assigned.
In order to assign the tides boundary, the following steps should be taken:
Figure 22 Set the tidal boundary.
7. Select the water level time series that created earlier, "Tides" as shown in Figure 25.
Figure 25 Assign tides boundary.
9. The open boundary often contains a lot of cells so it is not convenient to use the feature of Add to Adjacent cells that was used when we assigned the inflow boundary. In order to select multiple cells, we can to draw a line across all the cells as open boundaries. Then, click to Add by Polygon button (Figure 25).
10. Browse to "Open_BC Line.p2d" in Data folder then click Apply and then OK button. (See Figure 26).
11. Click Set All button in Figure 25 to assign tides to all cells.
12. The tides is now assigned to all open BC cells. (See Figure 27).
Figure 26 Selecting multiple BC cells by polyline/polygon.
Figure 27 Tidal BC cells assigned.
In order to optimize simulation time, the EFDC model can be set so that dry cells are ignored with Wetting and Drying frame. In this case we should set this condition as following:
Figure 28 Hydrodynamic Model Setup.
4. Click Modify button in Turbulence Options to set turbulence diffusion ( See Figure 29)
Figure 29 Turbulence Diffusion Settings.
The hydrodynamic model is ready for running test now. Normally a model is run for one vertical layer for initial calibration and more vertical layers are added later. To increase the number of vertical layers:
Figure 30 Setting the Vertical Layers.
We have now almost completed the hydrodynamic model. The final step is to set the model simulation time and model time steps.
Figure 31 Setting the model run time.
3. Select the EFDC_Explorer Linkage tab to set the frequency of the output of the EFDC results. Setting this to 60 minutes means that EFDC will save the output every 15 minutes for display of the model results in the EE. (Figure 32). Note that, smaller output frequency will create a larger output file.
Figure 32 Setting Linkage Output Frequency.
Figure 33 Browse to the EFDC executable file.
2. Select the Run EFDC icon to on the main form and click the Run EFDC+ button to run the model (Figure 34).
Figure 34 Run EFDC settings.
If you have correctly followed this example the model will start running and you will see the MS-DOS Window appear to shown the model results as see in Figure 35. Note that you can hit any characters on the keyboard to pause the simulation and check the model results. If you want to exit the simulation hit the same key, if you want to continue run then hit any other key.
Figure 35 Running EFDC Window.
To view the model simulation results the user can access ViewPlan, ViewProfile and View3D on the EE main form as shown in Figure 1.
Figure 36 Visualizing the EFDC+ solution.
Figure 37 ViewPlan Display Options.
There are few main features in the Toolbar that are very often used when analyzing the model results. Explanations for these buttons provided in Table 1 below.
Table 1 Description of main features in the Toolbar.
To plot the time series | |
To plot the vertical profiles | |
To general statistics | |
To plot the longitudinal profiles | |
To plot the water and mass flux | |
To make an animation | |
To plot and edit a polyline | |
To extract X,Y or I,J points | |
Apply polygon selection for cell modification | |
Copy cell property |