[Example 4] Flow in a real river(single cross section)

Select Solver

In the [Select Solver] window, Figure 81 , select [Nays2d+] and click [OK].


Figure 81 : Select Solver

Importing River Survey Data

In the window, Figure 82, select [Import], [Geographic Data], [Elevation(m)]


Figure 82 : Import river geographic data

Chose [single.riv] in the window, Figure 83 and open. The cross sectional survey data “single.riv” can be downloaded from, https://i-ric.org/yasu/fw/rivfiles/single.riv


Figure 83 : Select File

A message window may appear telling “Problems Fund i Data” as Figure 84 ,but just click [OK]


Figure 84 : Prblem Fund

Select [Middle point of left and right bank] in the [River Survey Data Import Setting] window as Figure 85 , and click [OK]


Figure 85 : River Survay Data Import Setting

Figure 86 riv file import complete.


Figure 86 : Import Complete

Grid Generation Conditions

From the main menu, select [Grid] and [Select Algorithm to Create Grid] as, Figure 87


Figure 87 : Select Algorithm to Create Grid

Select [Create grid from river survey data] from the window, Figure 88 , and click [OK].


Figure 88 : Create grid from river survey data

As shown in Figure 133 , a channel with cross sections with both ends’ blue circles are displayed.


Figure 89 : Setting Grid Create Condition Complete

Grid Generation

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


Figure 90 :Add Division Points(1)

Set [Division Number], set [4] in this example, and click [OK] (Figure 91 )


Figure 91 :Add Division Points(2)

Select one of the opposite side of the cross sectional line we selected in Figure 90 , right click, and chose [Add Division Points] (Figure 92 )


Figure 92 :Add Division Points(3)

Set [Division Number], set [4] as a same number we set in Figure 91 for the symmetry.


Figure 93 :Add Division Points(4)

Along the channel direction, division points are set all at once. Select [Grid], [Add Division Points Regionally] from the menu bar. ( Figure 94 )


Figure 94 :Add Division Points Regionally(1)

Chose [Specify target distance division points]. set distance [70] in this example, and click [OK].( Figure 95 )


Figure 95 :Add Division Points Regionally(2)

When the setup for division points are completed, a plane map with yellow circle points appears as Figure 96


Figure 96 :Set division points complete

Select [Grid], [Grid Create] from the menu bar.( Figure 97 )


Figure 97 :Grid Create(1)

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


Figure 98 :Grid Create(2)

Answer [Yes] when you asked [Do you want to map?] as Figure 99


Figure 99 :Mapping?

Completed grid is shown as Figure 100


Figure 100 :Grid Generation Complete

Bed configuration and channel shape can be confirmed by putting checking marks at, [Grid], [Node attributes] and [Elevation (m)]. ( Figure 101 )


Figure 101 :Confirmation of the Mapping Result

Computational Condition

Select [Calculation Condition] and [Setting] from the min menu as Figure 102 .


Figure 102 :Setting Computational Condition

Set [Time unit of discharge] as [Hour] and click [Edit], ( Figure 103 )


Figure 103 :Discharge Condition

Set discharge hydrography as Figure 104, constant for 3 hours with 2,000 qms, and click [OK].


Figure 104 :Input Discharge(2)

Set [Time and bed erosion condition] as Figure 105 .


Figure 105 :Time and bed erosion condition

Set “3D Velocity Profile” as shown in the figure Figure 106 , and click [Save and Close] to exit.


Figure 106 :3D Velocity Profile Settings

Launch Computation

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


Figure 107 :Launch Simulation(1)

Answer [Yes(Y)] when you asked [Save the project?] as Figure 108


Figure 108 :Launch Simulation(2)

Simulation starts. Figure 109


Figure 109 :Launch Simulation(3)

Click [OK] when the message [The solver finished calculation] as Figure 110


Figure 110 :Calculation finished

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 111 .


Figure 111 :2D Post-Process Window


n the object browser, put the check marks in “Scalar (node)” and “Depth[m]”, right-click and select “Properties”. The “Scalar Setting” window Figure 112 appears.


Figure 112 :Scalar Setting

Set the values as shown in Figure 112, and click [OK], then Figure 113 appears.


Figure 113 : Depth Plot

Display Background Image

Select from the main menu, [File]->[Property] ( Figure 114 )


Figure 114 :Select Property

From the “Project Property” window, click [Edit] at [Coordinate System] .. _04_haikei_02:


Figure 115 :Edit Coordinate System Setting

Input “Japan” in the [Search] window, and chose the one with “XII” from the items with [EPSG:….] as Figure 116 . See more detail on coordinate system of Japan at http://www.gsi.go.jp/sokuchikijun/jpc.html


Figure 116 :Select Coordinate System

Click [Close] of [Project Property] window of Figure 117


Figure 117 :Close Property Window

Put a check mark in a box in front of [Background Images(Internet)] and one of the items listed below, e.g., [Google Map (Satellite Image)] as Figure 118


Figure 118 :Background Image Import Complete

Velocity Vectors and Streamlines

Since the operation method is the same as the previous section, it will be omitted.

Particle Animations

Put check mark at [Particles] and [Velocity] in the object browser, put time bar back to zero, and push black button, ( Figure 119 ). Particle following the depth averaged velocity starts as Figure 120 .


Figure 119 :Particle Animation


Figure 120 :Particle movement by depth averaged velocity

Put check mark at [Particles] and [Surface Velocity] in the object browser. If you want to change color of particles, right click [Particle] and select [Property]. Set values as Figure 121 and click [OK]. Put the time bar back again to zero, and push black button. Particle following the surface velocity starts as Figure 122 .


Figure 121 :Particle Setting


Figure 122 :Particle movement following the surface velocity

If you select “Bottom Velocity” in the same procedure, you can show the particle animation following the bottom velocity ads Figure 123 .


Figure 123 :Particle movement following the bottom velocity