Welcome to Nays3DV example manual’s documentation!

Introduction

Nays3DV is 3Dimensional model developed for calculation of vertical and horizontal movement of fluid with density currents.

The Nays3DV solver is developed by Professor Yasuyuki Shimizu from Hokkaido University.

Density currents occured due to density differences, arise from temperature variations, suspended solids or dissolved materials. Therefore, formation and evolution of density currents are induced by natural conditions such as saline intrusions, oil spills etc. Density flow is important for problems in lakes, reservoirs and estuaries.

This manual explains the step by step guide of several examples in Nays3DV.

Explanations of this manual are based on the assumption that you have already installed iRIC in your computer. If you have not installed the iRIC software, download it from the following URL and install it on your computer.

URL: https://i-ric.org/en/download/ Software: iRIC version 4.x or later

Overview

Operational procedure

The main steps in using Nays3DV for your calculations are as shown in Figure 1.

: Nays3DV operational procedure

Launch Nays3DV

The following is the procedure to launch Nays3DV in iRIC.

When launching iRIC, the iRIC start page can be seen as Figure 2. Click on [Create New Project] in the [iRIC Start Page] window.

: Create new project_1

Then the [Select Solver] window will open as shown in Figure 3. Select [Nays3DV vertical 3D model] in the [Select Solver] window and click on [OK].

: Create new project_2

A window with the title bar untitled-iRIC 3.0.19.6343 [Nays3DV vertical 3D model] will appear as shown in Figure 4.

: Create new project_4

Nays3DV model is ready to use.

The basic steps to follow during a simulation in Nays3DV are,

1. Creation of the grid

2. Mapping the attributes to the grids

3. Setting the calculation conditions

4. Making a simulation

5. Visualization of results

Creating grids for Nays3DV

Grid generation for Nays3DV should be done using grid generator for Nays3DV.

For that select [Grid] , then select [Algorithm to Create Grid] and then [Grid Generator for Nays3DV] in [Select Grid Creating Algorithm] window as shown in Figure 5.

: Grid creation

Using grid generator for Nays3DV, it is possible to generate grids with flat bottom,sloped bottoms, perturbed bottom with a line or a cosine curve.

Setting the calculation conditions in Nays3DV

In calculation conditions, computational parameters such as calculation methods either CIP or upwind, computational domain (No of grids in z direction) and their spacing, boundary condition either closed or open boundaries and hydraulic boundary conditions, initial and boundary concentrations, Time and iteration parameters and physical parameters can be set.

After giving all the parameters, save and close. For setting up the calculation conditions, select [Calculation Condition] and then [Setting].

Then the [Calculation Condition] window will appear. Figure 6 shows the procedure.

: Calculation condition

Simulation of Nays3DV in iRIC

After creating the grid, mapping all the attributes and setting the calculation conditions, save the project as a .ipro or a project.

If save as a .ipro it will be a one single file and requires less space. When the results files are huge, its not possible to save as an *.ipro file. If save as a project it will be in a folder with several subfolders.

Check the node attributes and cell attributes to see whether the data are properly mapped. It is possible to edit the data there if needed.

After all the modifications save the project one last time and select [Simulation] and [Run] as shown in Figure 7. Before the simulation starts, you will be asked to save again. If so click on [Save] again.

: Simulation

Visualization of results of Nays3DV in iRIC

After the simulation end, select [Calculation Results] and [Open new 3D Post-processing Window] or simply click on the 3D post-processing window icon.

A window will appear as shown in the Figure 8.

: Visualization of results

Tick on any parameter in the object browser and adjust properties by right clicking on it.

It is possible to add contours, iso surfaces, arrows, stream lines and particles. For contour setting, should go to [contour] in [object browser] and right click. Contour setting window will appear. Then have to slect the physical value need to plot such as concentration, pressure, eddy viscosity, sigma, position, 3d obstacle, discharge, x-velocity, y-velocity, z-velocity or 3Dvelocity magnitude.

Then should add the faces required. For each face have to select the direction i,j,k and their ranges.

Direction i is chosen to draw a cross sectional figure.

For arrow setting,[Object Browser], [Arrow]. Then right click on [Arrow] and [property] will appear. Arrow setting window will appear upon click on property.

It is neccessary to add faces here which are required to plot.

For isosurface setting, select [Object Browser], [Isosurfaces] and right click, [Add]. Isosurface setting window will appear. There the physical values such as concentration, pressure, eddy viscosity, sigma, position, 3d obstacle, discharge, x-velocity, y-velocity, z-velocity or 3Dvelocity magnitude which need to be plot can be selected.

The region to be plotted and iso value and the minimum and maximum values need to be given.

The plot can be viewed 3D and rotate with right mouse click+ctrl key.

Animation of the variation can be seen with the animation icon.

Examples

This chapter describes the step by step guide of various kinds of examples.

Example 01: 3D density currents in a pond

Purpose

To understand the basic operation of Nays3DV in iRIC by calculating the current field due to a density difference in a pond with an open surface.

Creation of the calculation grid and setting the initial conditions

“Before starting the project it is safer to save the project either as ipro or as a project. Current project is saved as an ipro. Save the project by selecting, [File][save as File(*.ipro)] as shown in “Figure 9.

: Save the project

The grid for the Nays3DV model can be created only by using grid generator for Nays3DV.

Select[Grid] [Select Algorithm to Create Grid] then select [Grid Generator for Nays3DV] as shown in Figure 10.

: Grid creation

Now the grid creation dialogue will appear as shown in Figure 11. It is possible to select the channel shape as Straight channel or cubic box, sine generated meandering channel or Kinoshita meandering channel. In this example select straight channel or cubic box option.

: Grid creation

Adjust the channel length and number of grids in x and y directions as required. However, there is a maximum limit of the number of grids.

Then we can give channel bed condition. As here we use the default condition flat(no bar), no modifications are needed.

If new grids are added or width is varied it is possible to set them. As in this example no grids added and no width variations, no modifications are needed in them.

Initial water surface profile tab is used to give downstream depth, water surface slope and initial water surface purtavation. It can be seen as shown in Figure 12.

: Grid creation

Here the water surface shape can be adjusted either as flat, linear line or a cosine curve. If they are selected as cosine shape or linear, perturvation direction needs to be adjusted either as x direction, y direction or both x and y directions.If perturvation direction is given, amplitude of the perturvation and wave number also has to be given. In this example, water surface shape is given as cosine curve and water surface perturvation direction as x direction. Amplitude of the perturvation is 0.1 and wave number of the perturation is 1.

After giving the channel shape parameters and bed elevation and depth parameters, create grid. Then the created grid will appear as shown in Figure 13. A confirmation message box will appear asking do you want to map geographic data to grid attributes. Simply select yes and geographic data given in reference elevation and average depth will be mapped to the grid.

: Grid creation

However, later if new conditions of temperature, concentration,obstacle cells etc are added, should execute the attribute mapping again.

Now, add a new concentration boundary using a polygon as shown in Figure 14. [Initial Concentration] [Add] [Polygon] when the plus mark appear draw the polygon as required. The cells used for the boundary need to be fully covered by the drawn polygon.

: Adding a concentration boundary

After drawing the polygon, edit the values of the initial concentration of the drawn polygon as shown in Figure 15.

: Assign values for the concentration boundary

In this example initial concentration is set to 0.03. The upper limit of concentration is the maximum level that the concentration boundary affect. Since in thsi example it is set as -2m and bottom level also -2m, though a density boundary is given it doesnt affect to the flow. To have an effective boundary this should be about -1 m or so.

upper limit of concentration can be defined as shown in Figure 16.

: Concentration boundary

Now the new concentration needs to be mapped to the grids using, [Grid] [Attributes Mapping] and [Execute].

Then select the components needed to map. Select the parameters which changed the value. In this example it is concentration boundary. Therefore, concentration boundary (c_bound) is ticked as shown in Figure 17.

: Attributes mapping

After successful mapping of the attributes, it can be seen from the cell attributes and node attributes. Also boundary given will appear as shown in figure with the name.

In this example check it in cell attributes.

In the [Object Browser] [Grid] [Cell Attributes] [Initial Concentration] as shown in Figure 18.

: Attributes mapping check

As shown in the figure, concentration boundary is mapped properly.

It is always better to check the mapping situation before the simulation. If the elevation mapping is not completed properly simulation will stop giving an error.

Setting the calculation conditions and simulation

Next, calculation conditions need to be set.

For that, select [Calculation Conditions] and [Settings].

Then the calculation conditions window will open as shown in Figure 19. Input the values as shown in figure for computational parameters. Here it is possible to set with density flow or without density flow. For velocity advection term and concentration advection term it is possible to use either CIP method or upwind method. In this example CIP method is used.

In the computational domain it is required to give number of grids in z direction. According to this the Z direction grids in the domain will be created.

: Setting Calculation conditions

In this example, all the four boundaries are closed boundary as this is a closed tank.

As all the four boundaries are closed boundaries, hydraulic boundary conditions and initial and boundary concentration settings are inactive as shown in figures below. However, as a concentration boundary is given, should click yes for density boundary condition.

: Setting Calculation conditions-Hydraulic boundary condition

: Setting Calculation conditions-initial and boundary concentrations

Then input parameters for time and iteration parameters as shown in Figure 22.

: Setting Calculation conditions-Time and iteration parameters

Time and iteration parameters are important for simulation stability.

Computational time step needs to be set considering the CFL condition according to the grid size.

If the computation fails at the initial stage, change the time step to a smaller value and try again.

Then adjust the physical parameters as shown in Figure 23.

: Setting Calculation conditions-Physical parameters

Physical parameters need to be adjusted according to the fluids used. In this example default values are used.

After setting all the calculation parameters, save and close the window.

Then run the simulation with [Simulation] [Run] as shown in Figure 24.

: Simulation

A message will come recommending to save the project as shown in Figure 25. Click yes and save the project again and simulate.

: Save

The simulation will run as shown in Figure 26.

: Simulation in progress

Visualization of results

After the computation is stopped, results can be viewed from [Calculation Results] [Open new 3D Post-Processing Window] as shown in Figure 27 or by clicking on 3D post-processing window icon.

: Viewing results

The 3D post processing window will appear as shown in Figure 28

: Viewing results

In post processing window, the parameters need to be viewed can be selected in object browser. They can be selected either as contours, isosurfaces, arrows, streamlines or particles.

To see concentration contours, go to [contours] in [object browser] and right click there. Then we can add and a contour setting dialoge box will appear.

As shown in Figure 28 it is spossible to add contours of either concentration, pressure, eddy viscosity, sigma, position, 3d obstacle,discharge, x-velocity, y-velocity, z-velocity or 3Dvelocity magnitude.

As shown in the Figure 29, it is possible to add faces which need to be viewed and should adjust the i, j, k ranges of them. Can add multiple faces too. Value ranges, colour ranges as our selected cases can be adjusted.

: Viewing results- Contour setting

In this example two faces are added to visualize 3D velocity magnitude.

The same way arrow setting also can be done by right clicking [Arrow] in [Object Browser] and [Property] . Then arrow setting window will appear as shown in Figure 30

: Viewing results - Arrow setting

Plot can be viewed in 3D and move as our preferrred direction with right mouse click+ctrl key.

The Figure 31 is a representation of 3D velocity magnitude in two faces with arrows.

: Viewing results - 3D velocity representation

The animation of the movement can be viewed with animation buttons in top of the3D post-processing window.

Example 02: Upward flow in a tank

Purpose

To calculate the density currents in an upward flow originated from a tank bottom. A low density boundary which has a lesser density than the background density generates this flow in a tank.

Creation of calculation grid and setting initial conditions

Create the calculation grid using [Grid] [Select Algorithm to Create Grid]. Then select Grid Creation Algorithem window will appear and then select [Gird Generator for Nays3DV] in select grid creating algorithm window.

Then grid creation window will appear. Select channel shape as shown in Figure 32.

: Grid creation : Computational domain

Then we can give channel bed condition. As here we use the default condition flat(no bar) no modifications are needed.

If new grids are added or width is varied it is possible to set them. As in this example no grids added and no width variations, no modifications are needed in them.

Initial water surface profile tab is used to give downstream depth, water surface slope and initial water surface purtavation. It can be seen as shown in Figure 33.

: Grid creation : Initial water surface profile

Here a tank is selected with a flat bed. After giving all the parameters as given in figures, select [Create grid]. Here a confirmation dialogue box will appear to map geographic data to grid attributes. Select yes and it will map the geographic data to the created grid.

The grid will be created as shown in Figure 34.

: Grid creation : Created Grid

Then by selecting node attributes and bed elevation in object browser, [Object Browser] - [Grid] - [Node attributes] - [Bed Elevation (m)], it is possible to see the geographic data mapped grid as shown in Figure 35.

: Grid creation : Created Grid after mapping geographic data

It is always safer to see the attributes after mapping.

Now save the project with [File] [Save project as .ipro].

Setting the calculation conditions and simulation

Give the calculation conditions with, [Calculation Condition] [Settings].

Calculation cndition window will appear. Give computational parameters as shown in Figure 36.

: Calculation_condition : Computational parameters

Now give the [Hydraulic Boundary Conditions]. Since the boundary conditions for this simulation were given as closed boundaries in computational parameters, hydraulic boundary conditions window is inactive in this example as shown in Figure 37.

: Calculation_condition : Hydraulic Boundary Conditions

Now give [Initial and Boundary Concentration] as shown in Figure 38.

: Calculation_condition : Initial and Boundary Concentration

Here background concentration is the concentration in the tank and purturbed concentration is concentration of the down object which we create. In an upflow it is necessary to give initial purturbed concentration a lower value than the background concentration. Otherwise the upward flow won’t occur.

In the initial concentration distribution it is necessary to select the area of new concentration in all the directions i, j, k start and end grids.

Give time and iteration parameters as shown in Figure 39.

: Calculation_condition : Time and iteration parameters

Give physical parameters as shown in Figure 40.

: Calculation_condition : Physical parameters

After setting the calculation conditions, save the project by clicking on save tab. Now start simulation by, [Simulation] [Run]. Simulation will start and after some time it will finish showing the message the solver finished the calculation.

Visualization of results

Open 3D post processing window by selecting, [Calculation Results] [Open new 3D Post-Processing Window].

Select any parameter in [Object Browser], [iRIC Zone].

In this example isosurface is selected as shown in Figure 41. When [Object Browser] - [Isosurface] - [Add] is selected, we can add isosurface of any parameter such as concentration, pressure, position, eddy viscosity, velocity etc. In this example concentration is selected.

: Visualization of results : isosurfaces

In isosurface setting window, it is necessary to set physical value such as concentration, pressure, velosity etc which we need to plot. In value setting , we can see min value and max value as shown in Figure 42. Depending on our requirement we can select a value in between that min and max value.

: Isosurface setting

Then we can select the colour for the isosurface as shown in Figure 43.

: Colour setting

Then we can see the isosurface of concentration as shown in Figure 44.

: Visualization of results : isosurfaces

Initial and final isosurfaces can be seen as shown in Figure 45.

: Isosurface concentration

We can add arrows or contours to the plot as required.

To plot a concentration contour plot, go to [Object Browser] - [Contours] - right click at contours [Add]. Then contour setting window will appear as shown in Figure 46.

: contour setting : concentration

Here it is neccesary to add faces we nee to plot concentration. We can adjust the locations we need to plot by selecting region.

Figure 47 shows the concentration plot of the Zx plane.

: contour setting : concentration

Example 03: Dropping object inside a tank

Purpose

To calculate the gravity driven flow when a density difference occurred in vertical direction such as falling a heavy liquid from the top.

Creation of the calculation grid and setting the initial conditions

As explained in the other examples and the introduction, create the grid using, [Grid], [Select Algorithm to Create Grid] and then select [Grid Generator for Nays3DV]. Then the grid creation window will appear.

In grid creation window, give channel shape parameters as shown in Figure 48.

: Grid creation : Chanel Shape

Then we can give Chanel bed condition. As here we use the default condition flat(no bar), no modifications are needed.

If new grids are added or width is varied it is possible to set them. As in this example no grids added and no width variations, no modifications are needed in them.

Initial water surface profile tab is used to give downstream depth, water surface slope and initial water surface purtavation. It can be seen as shown in Figure 49. After giving all the parameters click on [Create Grid].

: Grid creation : Bed elevation and Depth

Then the grid is created and a confirmation message box will appear asking to map the geographic data as shown in Figure 50. and click on [Yes].

: Grid creation : Mapping geographic data to the grid

This will map the geographic data to the grid and the mapped grid can be seen as shown in Figure 51.

: Grid creation : Mapping geographic data to the grid

Save the project with [File], [Save as .ipro] or [Save as Project] as in Figure 52.

: Save as ipro

Setting the calculation conditions and simulation

Set the calculation conditions with, [Calculation Condition], [Setting].

Calculation condition window will open.

Set computational parameters as shown in Figure 53.

: Calculation Condition : Computational Parameters

Then give hydraulic boundary conditions. Since the boundary conditions are closed boundaries , boundary condition window is inactive as shown in Figure 54.

: Calculation Condition : Boundary Conditions

Then give initial and Boundary concentrations as shown in Figure 55.

: Calculation Condition : Initial and Boundary Concentrations

Here background concentration is the concentration inside tank and perturbed concentration is concentration of the dropping item. To drop and go down the tank, the purturbed concentration should be higher than the background concentration.

The i, j, k start and end locations of the purturbed concentration should be given as shown in above figure.

Then the time and iteration parameters are give as shown in Figure 56.

: Calculation Condition : Time and Iteration parameters

Then give the physical parameters as given in Figure 57.

: Calculation Condition : Physical Parameters

After setting the calculation conditions, save and close the calculation condition window.

Save the project again. Now start the simulation by [Simulation], [Run].

The end of simulation can be seen as shown in Figure 58.

: End of simulation

Visualization of results

After calculation solver stopped, go to [Calculation Results], [Open new 3D Post-Processing Window].

Here it is easy to visualize as isosurfaces. Go to [Object Browser] - [iRIC Zone] - [Isosurfaces] and right click on [Isosurfaces]. Isosurface setting window will appear as shown in Figure 59.

: Visualization of results : Isosurface setting

Iso value need to be set and the min and max value can be used as a guide to set Iso value.

Colour also need to be set to be seen nicely. Default colour is white and if the colour setting is forgetted, isosurface can’t be seen.

The movement of concentration can be seen as shwon in Figure 60.

: Visualization of results : Isosurface of concentration

If need to visualize the concentration as countours, goto [Object Browser] - [iRICZone] - [Contours]. Right click on contours and [Add]. Contour Setting window will appear as shown in Figure 61.

: Visualization of results : Contours Setting

Contours of concentration at the start and end can be seen as shown in Figure 62.

: Visualization of results : Contours of concentration

Example 04: 3D density currents in a closed tank with sloped bottom

Purpose

Calculate the vertical 3D flow over a sloped bottom. In this example a sloped channel with closed boundaries is used. No concentration boundary is given. However, initial concentration is given.

Creation of the calculation grid and setting the initial conditions

As explained in the other examples and the introduction, create the grid using, [Grid], [Select Algorithm to Create Grid] and then select [Grid Generator for Nays3DV]. Then the grid creation window will appear.

In grid creation window, give Chanel Shape parameters as shown in Figure 63.

: Grid creation : Channel shape parameters

Then we can give channel bed condition. As here we use the default condition flat(no bar) no modifications are needed.

If new grids are added or width is varied it is possible to set them. As in this example no grids added and no width variations, no modifications are needed in them.

Initial water surface profile tab is used to give downstream depth, water surface slope and initial water surface purtavation. It can be seen as shown in Figure 64 and click on [Create Grid]. Here the bed is given as a sloped bed varying linearly in x direction.

: Grid creation : Bed elevation and Depth

Then the grid is created and a confirmation message box will appear asking to map the geographic data as shown in Figure 65 and click on [Yes].

: Grid creation : Mapping geographic data to the grid

This will map the geographic data to the grid and the mapped grid can be seen as shown in Figure 66.

: Grid creation : Mapping geographic data to the grid

Save the project with [File], [Save as .ipro] or [Save as Project] as in Figure 67.

: Save as ipro

Setting the calculation conditions and simulation

Set the calculation conditions with [Calculation Condition], [Setting].

Calculation condition window will open.

Set computational parameters as shown in Figure 68.

: Calculation Condition : Computational Parameters

Then give hydraulic boundary conditions. Since the boundary conditions are closed boundaries , boundary condition window is inactive as shown in Figure 54.

: Calculation Condition : Boundary Conditions

Then give initial and boundary concentrations as shown in Figure 70.

: Calculation Condition : Initial and Boundary Concentrations

Here initial density distribution is given in calculation conditions. For that the i, j, k start and end locations of the purturbed concentration should be given as shown in above figure.

Then the time and iteration parameters are give as shown in Figure 56.

: Calculation Condition : Time and Iteration parameters

Then give the physical parameters as given in Figure 72.

: Calculation Condition : Physical Parameters

After setting the calculation conditions, save and close the calculation condition window.

Save the project again. Now start the simulation by [Simulation], [Run].

Visualization of results

After calculation solver stopped, go to [Calculation Results], [Open new 3D Post-Processing Window].

In this example, water surface position, concentration and arrows will be plotted. For that, [Object Browser] - [iRICZone] - [Contours] right click on contours and [Add]. Then the contour setting window will appear as shown in Figure 73. Select [position] in value setting. Add face and set their domain as shown in figure.

: Visualization of results : Contour Setting.

After the contour setting for the position, plot will be as shown in Figure 74.

: Visualization of results : Position

To set the concentration, [Object Browser] - [iRICZone] - [Contours] right click on contours and [Add]. Then the contour setting window will appear as shown in Figure 75. Select [Concentration] in value setting. Add face and set their domain as shown in figure. For the colour setting use custom colour settings as shown in figure. Here three colors are used.

: Visualization of results : Contour Setting for Concentration.

After the contour setting for the concentration, plot will be with position and concentration as shown in Figure 76.

: Visualization of results : Concentration and water surface position

Then set the isosurface as shown in Figure 77 .

: Visualization of Results : Concentration Isosurface setting

Then add the arrows to the plot. For that, right click on arrows and arrow setting will appear as shown in Figure 78.

: Visualization of results : Arrow setting

After the arrow setting the plot will be with position of water surface, concentration and velocity vectors as shown in Figure 79.

: Visualization of results

The animation of the movement can be viewed with animation buttons in top of the 3D post-processing window.

Example 05 : Free surface in a 3D density tank

Purpose

To calculate free surface in a closed channel. In ths example channel is a closed channel with a sloping bed and initial water surface is a purtubed as a cosine shape. Only water is simulated. No density flow.

Creation of calculation grid and setting initial conditions

As explained in the other examples and the introduction, create the grid using, [Grid], [Select Algorithm to Create Grid] and then select [Grid Generator for Nays3DV]. Then the grid creation window will appear.

In grid creation window, give channel shape parameters as shown in Figure 80.

: Grid creation : Computational Domain

Then we can give channel bed condition. As here we use the default condition flat(no bar), no modifications are needed.

If new grids are added or width is varied it is possible to set them. As in this example no grids added and no width variations, no modifications are needed in them.

Initial water surface profile tab is used to give downstream depth, water surface slope and initial water surface purtavation. It can be seen as shown in Figure 81. After setting all the parameters click on [Create Grid]. Here the bed is given as a sloped bed varying linearly in x direction.

: Grid creation : Bed elevation and Depth

Then the grid is created and a confirmation message box will appear asking to map the geographic data as shown in Figure 82 and click on [Yes].

: Grid creation : Mapping geographic data to the grid

This will map the geographic data to the grid and the mapped grid can be seen as shown in Figure 83.

: Grid creation : Mapping geographic data to the grid

Setting the calculation conditions and simulation

Set the calculation conditions with, [Calculation Condition], [Setting].

Calculation condition window will open.

Set computational parameters as shown in Figure 84.

: Calculation Condition : Computational Parameters

Then give hydraulic boundary conditions. Since the boundary conditions are closed boundaries , boundary conditions are inactive as shown in Figure 85. However, initial water surface elevation is given as read from geomatric data.

: Calculation Condition : Boundary Conditions

As only water is modeled, initial and boundary concentrations window is inactive as shown in Figure 86.

: Calculation Condition : Initial and Boundary Concentrations

Then the time and iteration parameters are given as shown in Figure 87. Here as we calculate the free surface boundary , need to set yes for free surface calculation.

: Calculation Condition : Time and Iteration parameters

Then give the physical parameters as given in Figure 88.

: Calculation Condition : Physical Parameters

After giving the calculation conditions, [Save and close].

Save the whole project one more time with clicking on save icon and start to run the program by, [Simulation] [Run]. Program will start to run.

When the simulation is finished, a dialogue box will appear with the message simulation stopped.

Visualization of results

Now go to 3D post processing icon or [Calculation Result][Open new 3D Post-Processing Window]. The 3D post processing window will appear.

In this example plotting the graphs will be demonstrated. For that, select the line graph icon as shown in Figure 89. Then the data source setting window will apear as in the figure.

: Visualization of results :

Then select the x axis (Here it is selected as time). It is possible to select as Time, i, j or k. Then need to select the data need to be plotted in y axis from the three dimensional data set and click on Add. Then that parameter will move to selected data side. Here it is position. Therefore, our plot will be Position vs Time as shown in Figure 90.

: Visualization of results :

As shown in the down of the figure, we can select the i, j, k locations we need to check from the controller by controler bar or typing in the box. Here i = 21, j = 4 and k = 6. Likewise it is possible to plot any location.

There are several options we can do for graphs as shown in the above figure such as csv export, snap shot, axis setting, marker setting etc.

Then if the distance and position need to be plotted, click on the graph icon as before and select x axis as i and y axis from the three dimensional data. Here position is slected as shown in Figure 91.

: Visualization of results :

Therefore, our plot will be Position vs Distance as shown in Figure 92.

: Visualization of results :

Example 06: Open channel flow

Purpose

To calculate the density currents in an open channel. In this example channel is open both upstream and downstream. Constant dischargeis given from upstream and downstream water surface is oscilating as same as sea water oscilating at a river mouth.

Creation of calculation grid and setting initial conditions

Create the calculation grid using [Grid] [Select Algorithm to Create Grid] and then select [Gird Generator for Nays3DV] in select grid creating algorithm window.

In grid creation window, give channel shape parameters as shown in Figure 63.

: Grid creation : Computational Domain

Here the bed is given as a sloped bed with 0.1 slope.

Then we can give channel bed condition. As here we use the default condition flat(no bar) no modifications are needed.

If new grids are added or width is varied it is possible to set them. As in this example no grids added and no width variations, no modifications are needed in them.

Initial water surface profile tab is used to give downstream depth, water surface slope and initial water surface purtavation. It can be seen as shown in Figure 94 and click on [Create Grid].

: Grid creation : water surface elevation and Depth

Then the grid is created and a confirmation message box will appear asking to map the geographic data as shown in Figure 95 and click on [Yes].

: Grid creation : Mapping geographic data to the grid

This will map the geographic data to the grid and the mapped grid can be seen as shown in Figure 96.

: Grid creation : Mapping geographic data to the grid

Now save the project with [File] [Save project as .ipro].

Setting the calculation conditions and simulation

Give the calculation conditions with, [Calculation Condition] [Settings]

Set computational parameters as shown in Figure 97.

: Calculation Condition : Computational Parameters

Then give hydraulic boundary conditions. Since the boundary conditions are Open boundary , boundary condition has to give as shown in Figure 98.

: Calculation Condition : Boundary Conditions

Then give initial and boundary concentrations as shown in Figure 99. Since only teh water is simulated and no density flow, initial and boundary concentration window is inactive as shown in the following figure.

: Calculation Condition : Initial and Boundary Concentrations

Then the time and iteration parameters are given as shown in Figure 100.

: Calculation Condition : Time and Iteration parameters

Then give the physical parameters as given in Figure 101.

: Calculation Condition : Physical Parameters

After setting the calculation conditions, save the project by clicking on save tab. Now start simulation by, [Simulation] [Run]. Simulation will start and after some time it will finish showing the message the solver finished the calculation.

Visualization of results

Open 3D post processing window by selecting, [Calculation Results] [Open new 3D Post-Processing Window].

In this example, Concentration contours and velocity arrows will be plotted. For that, In 3D post processing window, Go to [Object Browser] - [Contours] and right click on conturs and click on [Add]. Then contour setting window will appear as shown in Figure 102.

: Visualization of Results : Contour Setting

Set the parameters as shown in the above figure such as; physical value to the magnitude of velocity and Add the faces need to plot the velocity magnitude and set their regions.

Then to plot the arrows, go to [Object Browser] - [Arrow] then right click on arrow and then click on [Property]. Arrow setting window will appear as shown in Figure 103 Then add the faces that arrows need to plot and their i, j, k regions.

: Visualization of Results : Arrow Setting

Now visualize both velocity magnitude plot and arrows on it in selected faces as shown in Figure 104.

: Visualization of Results : Velocity contours and arrows

Example 07: Density flow in a rectangular channel

Purpose

To calculate the density currents in a rectangular tank. In this example density currents are simulated in closed tank with flat bottom. Initial concentration is given and additional concentration boundaries are not given.

Creation of calculation grid and setting initial conditions

Create the calculation grid using [Grid] [Select Algorithm to Create Grid] and then select [Gird Generator for Nays3DV] in select grid creating algorithm window.

Then the grid creation window will appear.

In grid creation window, give channel shape parameters as shown in Figure 105.

: Grid creation : Computational Domain

Then we can give channel bed condition. As here we use the default condition flat(no bar) no modifications are needed.

If new grids are added or width is varied it is possible to set them. As in this example no grids added and no width variations, no modifications are needed in them.

Initial water surface profile tab is used to give downstream depth, water surface slope and initial water surface purtavation. It can be seen as shown in Figure 106 . After setting all the parameters click on [Create Grid]. Here the bed is given as a sloped bed varying linearly in x direction.

: Grid creation : Water surface elevation and Depth

Then the grid is created and a confirmation message box will appear asking to map the geographic data as shown in Figure 107 and click on [Yes].

: Grid creation : Mapping geographic data to the grid

This will map the geographic data to the grid and the mapped grid can be seen as shown in Figure 108.

: Grid creation : Mapping geographic data to the grid

Now save the project with [File] [Save project as .ipro].

Setting the calculation conditions and simulation

Set the calculation conditions with [Calculation Condition], [Setting].

Calculation condition window will open.

Set computational parameters as shown in Figure 109.

: Calculation Condition : Computational Parameters

Then give hydraulic boundary conditions. Since the boundary conditions are closed boundaries , boundary condition window is inactive as shown in Figure 110.

: Calculation Condition : Boundary Conditions

Then give initial and Boundary concentrations as shown in Figure 111.

: Calculation Condition : Initial and Boundary Concentrations

Here initial density distribution is given in calculation conditions. For that the i, j, k start and end locations of the purturbed concentration should be given as shown in above figure.

Then the time and iteration parameters are give as shown in Figure 112.

: Calculation Condition : Time and Iteration parameters

Then give the physical parameters as given in Figure 113.

: Calculation Condition : Physical Parameters

After setting the calculation conditions, save the project by clicking on save tab. Now start simulation by, [Simulation] [Run]. Simulation will start and after some time it will finish showing the message the solver finished the calculation.

Visualization of results

Open 3D post processing window by selecting, [Calculation Results] [Open new 3D Post-Processing Window].

In this example, isosurface concentration with arrows are plotted. For that, go to [Object Browser] - [Isosurfaces] and right click on isosurfaces. Then click on [Add]. Isosurface setting window will appear as shown in Figure 114.

: Results Visualization : Isosurface setting

In the isosurface setting window, give physical value as concentration, and value setting as 0.015. Value setting can be done using the min and max value as a guide and can set to a value in between. Then the color has to be set and if no color is set, the isosruface cannot be seen as the default color is white.

created isosurface can be seen as shown in Figure 115.

: Results Visualization : Isosurface of Concentration

To add arrow to the plot, go to [Object Browser] - [Arrow] and right click on arrow. Then click on [Property]. Arrow setting window will appear as shown in Figure 116.

: Results Visualization : Arrow Setting

Here add a face and select direction and region where arrow need to plotted. and the length of the arrow can be adjusted as shown in the above fig. This can be changed according to the visualization requirement.

The final figure with the isosurface of concentration and arrows for the currents can be seen as shown in Figure 117.

: Results Visualization : Isosurface of concentration with currents

Example 08: Rectangular channel with an osbtacle

Purpose

To calculate the density currents in a rectangular channel with an obstacle. In this example density currents are simulated in a closed rectangular channel with a sloped bottom with obstacles.

Creation of calculation grid and setting initial conditions

Create the calculation grid using [Grid] [Select Algorithm to Create Grid] and then select [Gird Generator for Nays3DV] in select grid creating algorithm window. Then the grid creation window will appear.

In grid creation window, give channel shape parameters as shown in Figure 118. Here the bed is given as a sloped bed varying linearly in x direction.

: Grid creation : Computational Domain

Then we can give channel bed condition. As here we use the default condition flat(no bar), no modifications are needed.

If new grids are added or width is varied it is possible to set them. As in this example no grids added and no width variations, no modifications are needed in them.

Initial water surface profile tab is used to give downstream depth, water surface slope and initial water surface purtavation. It can be seen as shown in Figure 119. After setting all the parameters, click on [Create Grid].

: Grid creation : Water surface elevation and Depth

Then the grid is created and a confirmation message box will appear asking to map the geographic data as shown in Figure 120 and click on [Yes].

: Grid creation : Mapping geographic data to the grid

This will map the geographic data to the grid and the mapped grid can be seen by selecting in object browser [Grid] - [Node attributes] - [Elevation] .

Now a obstacle cell needs to be added to the grid. For that, go to [Object Browser] - [Geographic Data] - [Obstacle cell]. Now right click on obstacle cell and click on [Add polygon group]. Now it is possible to draw the obstacle polygon and after drawing the polygon, edit osbtacle box will apear to edit the polygon. There it is possible to set the obstacle cell or normal cell as shown in Figure 121.

: Grid creation : Adding an Obstacle

Now the top elevation of the obstacle has to be given. For that, go to [Object Browser] - [Geographic Data] - [Obstacle Top Elevation]. Now right click on obstacle top elevation and click on [Add polygon group]. Now it is possible to draw the obstacle top elevation polygon and after drawing the polygon, edit osbtacle top elevation value box will apear to edit the polygon. There it is possible to set the obstacle top elevation value as shown in Figure 122.

: Grid creation : Obstacle top elevation

Here to have an effect from the obstacle, the obstacle top elevation is set as higher than the water surface.

Now the obstacle cell and obstacle top elevation need to be mapped to the grid. For that, go to [Grid] - [Attributes mapping] - [Execute]. Then the attribute mapping window will appear. Select Obstacle cell and Obstacle Top elevation as shown in Figure 123.

:Attributes mapping

Confirmation window will appear saying that attributes mapped properly.

It is possible to see the mapped attributes by ticking on cell attributes. [Object Browser] - [Grid] - [Cell Attributes] as shown in Figure 124.

:Attributes mapping check

Now save the project with [File] [Save project as .ipro].

Setting the calculation conditions and simulation

Set the calculation conditions with [Calculation Condition], [Setting].

Calculation condition window will open.

Set computational parameters as shown in Figure 125.

: Calculation Condition : Computational Parameters

Then give hydraulic boundary conditions. Since the boundary conditions are closed boundaries , mostparts of the boundary condition window is inactive as shown in Figure 126.

: Calculation Condition : Boundary Conditions

Then give initial and boundary concentrations as shown in Figure 127.

: Calculation Condition : Initial and Boundary Concentrations

Here initial density distribution is given in calculation conditions. For that the i, j, k start and end locations of the purturbed concentration should be given as shown in above figure.

Then the time and iteration parameters are give as shown in Figure 128.

: Calculation Condition : Time and Iteration parameters

Then give the physical parameters as given in Figure 129.

: Calculation Condition : Physical Parameters

After setting the calculation conditions, save the project by clicking on save tab. Now start simulation by, [Simulation] [Run]. Simulation will start and after some time it will finish showing the message the solver finished the calculation.

Visualization of results

Open 3D post processing window by selecting, [Calculation Results] [Open new 3D Post-Processing Window].

In this exmaple, Isosurfaces of concentration, 3D obstacle and arrows(3D velocity) will be plotted. For that, go to [Object Browser] - [Iso surfaces] and [Add]. Isosurface setting window will appear as shown in Figure 130.

: Visualization of Results : 3dObstacle Isosurface setting

Here set physical value as 3dObstacle and in value setting set value to 1. For the colour set a colour as shown in the above fig. If no colour is selected as the default colour is white, Obstacle may not be visible.

As the same way, set isosurface for concentration as shown in Figure 131.

: Visualization of Results : Concentration Isosurface setting

Then set the arrows for 3Dvelocity. For that, go to [Object Browser] - [Arrows] and right click on arrows. Click on [Property]. Then arrow setting window will appear as shown in Figure 132.

: Visualization of Results : Arrow setting

Here add the faces where the arrows need to be plot and their direction and range. Then adjust the arrow length.

The combined plot will be as shown in Figure 133.

: Visualization of Results : 3d velocity currents and concentration with the obstacle