# [Example 5] Flow in a Real River (Compound Cross section)¶

## Select Solver¶

In the [Select Solver] window, Figure 124 , select [Nays2d+] and click [OK].

## Importing River Survey Data¶

In the window, Figure 125, select [Import], [Geographic Data], [Elevation(m)] Figure 125 : Import river geographic data

Chose [single.riv] in the window, Figure 126 and open. The cross sectional survey data “compound.riv” can be downloaded from， https://i-ric.org/yasu/fw/rivfiles/compound.riv

A message window may appear telling “Problems Fund i Data” as Figure 127 ,but just click [OK]

Select [Middle point of left and right bank] in the [River Survey Data Import Setting] window as Figure 128 , and click [OK] Figure 128 : River Survay Data Import Setting

Figure 129 riv file import complete.

## Moving centerline¶

As shown in Figure 130 , move the centerline of the channel close to approximate center of the low water channel.

## Grid Generation Conditions¶

From the main menu, select [Grid] and [Select Algorithm to Create Grid] as, Figure 131 Figure 131 : Select Algorithm to Create Grid

Select [Create grid from river survey data] from the window, Figure 132 , and click [OK]. Figure 132 :Create grid from river survey data

As shown in Figure 133 , a channel with cross sections with both ends’ blue circles are displayed. Figure 133 : Setting Grid Create Condition Complete

## Grid Generation¶

Select any side of one of the cross section line, right click, and chose [Add Division Points].

Set [Division Number], set  in this example, and click [OK] (Figure 135 )

Select one of the opposite side of the cross sectional line we selected in Figure 134 , right click, and chose [Add Division Points] (Figure 136 )

Set [Division Number], set  as a same number we set in Figure 135 for the symmetry.

Along the channel direction, division points are set all at once. Select [Grid], [Add Division Points Regionally] from the menu bar. ( Figure 138 ) Figure 138 :Add Division Points Regionally(1)

Chose [Specify target distance division points]. set distance  in this example, and click [OK]．( Figure 139 ) Figure 139 :Add Division Points Regionally(2)

When the setup for division points are completed, a plane map with yellow circle points appears as Figure 140 Figure 140 :Set division points complete

Select [Grid], [Grid Create] from the menu bar.( Figure 141 )

Confirm the grid generation range painted with blue, and click [OK].

Answer [Yes] when you asked [Do you want to map?] as Figure 143

Completed grid is shown as Figure 144

Bed configuration and channel shape can be confirmed by putting checking marks at, [Grid], [Node attributes] and [Elevation (m)]. ( Figure 145 ) Figure 145 :Confirmation of the Mapping Result

## Computational Condition¶

Select [Calculation Condition] and [Setting] from the min menu as Figure 146 . Figure 146 :Setting Computational Condition

Set [Time unit of discharge] as [Hour] and click , ( Figure 147 )

Set discharge hydrography as Figure 148, constant for 3 hours with 2,000 qms, and click [OK].

Set [Time and bed erosion condition] as Figure 149 . Figure 149 :Time and bed erosion condition

Set “3D Velocity Profile” as shown in the figure Figure 150 , and click [Save and Close] to exit. Figure 150 :3D Velocity Profile Settings

## Launch Computation¶

From the menu bar, select [Simulation] and [Run].

Simulation starts. Figure 153

Click [OK] when the message [The solver finished calculation] as Figure 154

## Display Computational Results¶

After the companion finished, form the main menu, by selecting [Calculation Results] and [Open new 2D Post-Processing Window], a new Window appears as Figure 155 .

### Depth¶

In the object browser, put the check marks in “Scalar (node)” and “Depth[m]”, right-click and select “Properties”. The “Scalar Setting” window Figure 156 appears.

Set the values as shown in Figure 156, and click [OK], then Figure 157 appears.

### Display Background Image¶

Background images can be imported from Internet resources by the method described in the previous section. After setting the property of the coordinate system, put check marks in a box in front of [Background Images(Internet)] and one of the items listed below, e.g., [Google Map (Satellite Image)], the background image is imported and shown as Figure 158 Figure 158 :Background Image Import Complete

### Particle Animations¶

Particle animations can be played by the same procedure with the previous section. Figure 159 shows the particle animation using the depth averaged velocity, Figure 160 shows the particle animation using the surface velocity, and Figure 161 shows the particle animation using the bottom velocity. Figure 159 :Particle movement by depth averaged velocity Figure 160 :Particle movement by surface velocity Figure 161 :Particle movement by bottom velocity

From the main menu bar, select [File], [Continuous Snapshot /Movie/Google Export] as Figure 162

Chose [Next(N)] in Figure 163

Chose [Next(N)] in Figure 164

Chose [Next(N)] in Figure 165

Put check mark at [Output movie files], and click [Next(N)] in Figure 166

Set values as Figure 167 and click [Next]

Put check mark at [Output to the Google Earth], click [Next] in Figure 168

click [Finish] in Figure 169

Then a file “output.kml” is generated. You can now start playing by double clicking the “output.kml” as Figure 170