Film Loop

Once a solution has been created by SMS, you can use a number of features to view the results and adjust the model to better approximate the observed values. The easiest way to view the results from the RMA4 solution is to use the film loop. Before using the film loop, the RMA4 solution file must be imported:

1. Select File | Open.

2. Select madora.qsl, and push Open.

To create the film loop:

1. Select Data | Film Loop… to bring up the Film Loop Setup dialog.

2. Make sure Create New Filmloop is selected and click on the File Browser to save this new loop as smsloop1.avi

4. Turn on Scalar Data Set and make sure the Run Simulation Time goes from 0.0 to 24.0 and the Number of Frames is set to 49. Press Next.

5. Click the Display Options button .

6. In the Display Options, turn off everything but Elements and Contours.

7. Select the Contour Options tab and choose Color fill as the Contour Method. Select to Specify a range from a Min of 0.0 to a Max of 10.0. (This is done because when the stream flow enters the main channel, the concentration quickly drops to between 0.0 and 10.0 ppm.)

8. Push OK to get back to the Film Loop dialog.

9. Push Finish to start generating the film loop. Each frame of the film loop will be generated. After the film loop is done generating, a new window will come up to play the results.

10. Close the AVI application when you are finished watching the results.

You will notice how the concentration drops quickly as the pollutant enters the main channel. This occurs because the inflow from the small channel is 0.4% of the inflow from the main channel.

12.3 Case 2

In this case, a constituent is coming into Noyo Bay from a river. The files for this case can be opened by:

1. Select File | Open.

2. Select the file noyo1.sms from the tutorial\tut12_RMA4 directory. If you still have geometry open, you will be asked if you want to delete existing data. If this happens, click the Yes button.

The geometry will be displayed on the screen with the RMA2 boundary conditions as shown in Figure 12-2.

This mesh was initially created in English units and later converted to metric units to use in RMA4. The river flowing into Noyo Bay has a flow of 28.32 cms. The water surface elevation on the left side varies as the tide comes in and out over a 12-hour cycle repeated twice a day.

Figure 12-2 Noyo mesh

12.3.1 RMA4 Model Control

To set the model controls:

1. Select RMA4 | Model Control.

2. In the General tab, make sure the Start Time is set to 0.0, and set the Time

Step to 0.5 (h), the Total Time Steps to 49, and the Max Time to 24 (h).

3. In the Files tab, set the Last time step used from the RMA2 velocity file to 24.0 (hrs) and the Time subtracted from the RMA2 velocity file to 12.0 (hrs). This will cause RMA4 to use the last 12 hours of the RMA2 solution.

4. Turn on Specify RMA2 Solution File, and select noyo1.sol. 5. Make sure that Write RMA4 Solution File is checked.

6. Turn on Activate full report in the Informational Files section. 7. Click OK to exit the RMA4 Model Control dialog.

12.3.2 Boundary Conditions

For this model, a constant inflow of 100 ppm of a pollutant enters the bay from the river. To apply this boundary condition:

1. Select the Select Nodestring tool from the Toolbox.

2. Select the nodestring at the right side of the model and select RMA4 | Assign

BC.

3. Set a Constant Concentration of 100.0 (ppm) and push OK to exit the RMA4

Assign BC dialog.

12.3.3 Material Properties

To apply the diffusion:

1. Select RMA4 | Material Properties.

2. For each material make sure the X and Y diffusion coefficients (Dx and Dy)

are all set to 1.0 (m2_/s). 3. Push OK to exit the dialog.

12.3.4 Run RMA4

Save the noyo1.sms project and run RMA4 as you did for Case 1. After RMA4 runs, open the solution file noyo1.qsl.

12.3.5 Film Loop

Generate a film loop named smsloop2.avi using the same steps as for case 1 (Section 12.2.5) with the following exception:

• Do not set a range in the Data Range section of the Contour Options dialog.

12.4 Case 3

For this final case, we will view salinity intrusion into Noyo Bay. Open noyo2.sms. If you still have geometry open, you will be asked if you want to delete existing data. If this happens, click the Yes button.

12.4.1 RMA4 Model Control

To set the model times:

2. In the General tab, make sure the Start Time is set to 0.0, and set the Time

Step to 0.5 (h), the Total Time Steps to 49, and the Max Time to 24 (h).

3. In the Files tab, set the Last time step used from the RMA2 velocity file to 24.0 (hrs) and the Time subtracted from the RMA2 velocity file to 12.0 (hrs). This will cause RMA4 to use the last 12 hours of the RMA2 solution.

4. Turn on Specify RMA2 Solution File, and select noyo2.sol. 5. Make sure that Write RMA4 Solution File is checked.

6. Turn on Activate full report in the Informational Files section. 7. Click OK to exit the RMA4 Model Control dialog.

12.4.2 Boundary Conditions

For this model, a constant concentration of 8 ppm exists offshore and enters the bay from the left. To apply this boundary condition:

1. Select the Select Nodestring tool from the Toolbox.